This alternative Kindle, called the DX, is a super-size version of the popular Kindle 2, which arrived earlier this year. It sports a 9.7-inch screen, some 2.5 times as big as the surface area of the Kindle 2’s 6-inch display. It also sports a higher price tag — $489, versus $359 for its smaller sibling, which remains on the market.

Amazon’s Kindle DX

Like previous models, the Kindle DX allows you to shop for, and wirelessly download, any e-book in Amazon’s (AMZN) growing catalog — now about 275,000 titles. It uses the same easy-on-the-eyes screen technology as the smaller model but at a higher resolution. It still lacks color, and renders images only in gray scale. But the new DX adds a new capability: auto-rotation, which allows you to read in landscape mode.

This new, larger model isn’t primarily aimed at readers of standard books. It is targeted at three markets: textbooks, newspapers and other periodicals, and business documents in either Microsoft’s (MSFT) Word format or Adobe’s (ADBE) PDF format.

Unfortunately, I’ve been testing the Kindle DX and I didn’t like it nearly as much as the Kindle 2, which I own and enjoy using daily. While it performs its promised tasks adequately, I found that its size and weight made it awkward and tiring to hold for long periods of reading. It’s still fairly thin and light, but it’s 85% larger and heavier than the standard Kindle.

In addition, Amazon has degraded the user interface. To prevent the device from being even larger, the company had to remove the left-side page-turning buttons, confining all the controls to a vertical strip on the right. The keyboard at the bottom is also more vertically cramped.

If you’re left-handed, you have to spin the device around and rotate the screen to get buttons on the left, where they appear with their labels upside-down.

Similarly, if you choose to read in landscape mode, all the navigation controls, including the joystick for moving the cursor, will be awkwardly placed at either the top or bottom, far from where your hands are holding the device, and the keyboard essentially will be unusable.

In my view, the Kindle DX would have been a better product with on-screen touch controls that could instantly adapt to its size and orientation.

In reading standard books on the DX, I also encountered instances where the text on a page varied in shade from light gray to black.

I had mixed results with business documents. As with previous Kindles, you can either email personal documents to your device, for a fee, or drag them onto the Kindle via a cable, for free. But, unlike the smaller models, the new DX has PDF display capability built in, so it renders PDF files much more accurately than the older Kindles. That is a big improvement. It also allows you to view Excel and PowerPoint files if you save them in PDF format before sending them to your Kindle DX.

The Kindle DX, right, is a large-screen version of the popular Kindle e-reader, left.

I tried a variety of documents, and in many cases the results were great. The text was crisp, and the tables and graphics looked like they should. But I found that on some of these PDF documents, the text was too small to read. Yet, the Kindle lacks the ability to zoom in on PDF documents. You often can make the type larger by rotating to landscape mode, but this splits the PDFs into multiple pages, sometimes breaking them awkwardly.

Also, Amazon has raised its fees for converting and delivering business documents via email to all Kindles. The charge was formerly 10 cents a document. Now, it’s 15 cents per megabyte, which can add up if you load up your Kindle with lots of large documents. Most of my test documents, which were fairly small, cost over $1 each.

Newspapers looked about the same on the DX as they do on the smaller Kindles. Despite the larger screen, they don’t use traditional print or Web layouts, but a special Kindle layout that some users like a lot, but which I find annoying because it makes it harder to quickly scan multiple headlines.

The Kindle DX does have some nice touches. For the extra money, you not only get a larger screen, but also about twice the storage capacity. Also, because the screen is wider, you can adjust the margins on the DX, to obtain a line length that’s comfortable for your eyes and optimal for reading speed.

Amazon claims the same multiday battery life for the DX as for the Kindle 2. In my tests, I was able to go for several days of moderate reading without recharging, and much more if I turned off the wireless capability.

Although I wasn’t able to test college textbooks, I suspect they may be the killer app for this product. Many already are so expensive and heavy they could make the weight and price of the Kindle DX seem trivial in comparison.

But for standard books, I’d stick with the smaller, more comfortable Kindle 2.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.

Wireless cellphone earpieces can make people look faintly ridiculous as they stroll down the street or around the office, seemingly talking to themselves with ugly appendages sprouting from their heads. The pulsing blue lights on these things can make people look like robots. And these battery-powered gadgets, which use a power-hungry wireless technology called Bluetooth, are just one more thing to charge.

But such headsets are becoming more necessary, at least in the car. A growing number of cities and states are requiring all calls made while driving be conducted in a “hands-free” manner. Two more big states, California and Washington, will begin enforcing such laws in July. Unless drivers in these places have cars with costly built-in Bluetooth speakers and microphones, many will turn to wireless earpieces to make calls legally.

Now, two of the most important wireless earpiece makers are bringing out new models that attempt to make their products more attractive and functional. One is a new version of the Jawbone, which has become a leader in the high-priced end of the market. The other is a new model from Plantronics (PLT), which vies with Motorola (MOT) as the top seller of wireless earpieces.

I’ve been testing both the new $130 Jawbone, and the $150 Plantronics Discovery 925, and both work well, despite some drawbacks. Each worked properly with both an inexpensive Motorola Razr phone from Verizon (VZ) and a sophisticated Apple (AAPL) iPhone from AT&T (T). But I preferred the Jawbone, because of its technology and design.

The new Jawbone, made by a closely held San Francisco company called Aliph, is 50% smaller than the original Jawbone, which I reviewed in 2006. It continues to boast the original Jawbone’s signature feature: a remarkable ability to suppress background noise and isolate the wearer’s voice.

Jawbone performs this feat by using a sensor that touches your skin lightly to identify your voice through the vibration of the bones in your face. Using this information, its microphone can more easily distinguish your voice from background noise, and accurately suppress the latter.

This feature, originally called “Noise Shield” and now theatrically renamed “Noise Assassin,” really works. When the company first showed off the original Jawbone, it made live calls standing in front of things like weed whackers and boom boxes, and then turned the bone-sensing feature on and off to show the dramatic difference.

Aliph’s new Jawbone

In my tests of the new, much smaller Jawbone, I stood a few feet from a roaring vacuum cleaner, while on a phone call. The person I was calling could barely hear me with Noise Assassin turned off, but could clearly make me out when I turned it on.

By contrast, the Plantronics Discovery failed my noise test. It was useless anywhere near the vacuum cleaner. This was obviously an extreme case, but it served as a stand-in for other loud noises likely to be encountered in real life, like large trucks, or construction gear on the streets.

The biggest flaw in the original Jawbone, in my 2006 tests, was its performance in wind, which was poor. The Jawbone did much better in my latest tests. During a Jawbone call from a car with all the windows down and the sunroof open, my voice was easy to make out, according to the person I was calling. The new Plantronics earpiece did just as well in this wind test.

Plantronics claims its headset also enhances the voice of the person you are calling, a claim Aliph doesn’t make for the Jawbone. But, while voices sounded fine on the Plantronics, I couldn’t detect any difference between the two on that score.

Both gadgets are meant to be more stylish, and both will be available in multiple colors. But, while the Jawbone is just a smaller iteration of its original slab-like form, Plantronics has done something more radical with the Discovery 925: It has tried to make it look like jewelry. The Discovery’s electronics are housed in the diamond-shaped portion of the device that goes on the ear, and the microphone sits at the end of a long, V-shaped boom that is open in the center. Plantronics says the design is suitable for both genders, but admits it is a bit more aimed at women and at fashion-conscious men.

I believe some men wouldn’t feel comfortable wearing this new Plantronics model. It’s also longer than the Jawbone. But I did find it more comfortable to wear, since it doesn’t protrude as much into the ear.

The Plantronics claims longer talk time — five hours vs. four hours for the Jawbone, but the Jawbone claims longer standby time — eight days, vs. seven days for the Plantronics. The Jawbone weighs more, at 10 grams, compared with 8 grams for the Plantronics, but neither felt heavy on my ear.

I did prefer the Plantronics’ controls over the Jawbone’s. The former uses obvious buttons, while the latter employs unmarked, hidden buttons whose location you have to learn by touch.

Both of these earpieces do the job, but if you have to choose one, I’d pick the Jawbone.

• Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.

Corrections & Amplifications:

The Aliph Jawbone cellphone earpiece weighs 10 grams, and the Plantronics Discovery 925 earpiece weighs 8 grams. An earlier version of this column erroneously reported the products’ weights in ounces.

This interface is generally called “multitouch,” and it involves using one or more fingers on a screen or touchpad to perform special gestures that manipulate lists or objects on a screen — without moving a mouse, pressing buttons, turning scroll wheels or striking keys.

The best-known example of the interface is on Apple’s iPhone and iPod Touch devices. It allows you, for example, to rapidly flip through photos, lists of emails or song titles by merely “flicking” a fingertip on its screen, or to resize a photo by “pinching” the image with two fingers. And, this month, Apple moved some of these multitouch features onto a laptop, its new MacBook Air, where fingertip actions are performed on an oversized touchpad rather than on a screen.

Apple didn’t invent the multitouch concept. Academic and commercial researchers, and small, obscure companies, have been working on it for years. Apple is adapting the concept, adding its own ideas and popularizing it — just as it did in the 1980s with the mouse and the graphical user interface, which had also been invented elsewhere.

Rival companies are scrambling to add multitouch features to laptops and other digital gadgets. Synaptics, a leading supplier of touchpads for laptop makers who compete with Apple, has announced that shortly it will incorporate several multitouch features into its touchpads. Microsoft is producing a coffee-table-size computer called the Surface, meant for hotels, casinos and retail stores, that uses multitouch finger gestures to move around digital objects such as photos, play games and browse through product options. Hewlett-Packard developed a prototype of a similar multitouch coffee-table computer for home use.

Rotating a photo on Apple’s MacBook Air

And, in the back rooms of this month’s Consumer Electronics Show in Las Vegas, various cellphone makers, seeking to emulate the iPhone, were showing off their own unannounced efforts at multitouch. One prominent cellphone maker, Taiwan-based HTC, has already built a phone, called the Touch, which slaps a rudimentary multitouch interface on Microsoft’s Windows Mobile operating system.

The basic touch screen, of course, is an old and familiar thing. People use them every day to get money from ATMs or to check into flights at airport kiosks. Microsoft’s Tablet computers and Palm’s Treo cellphones, among others, use touch screens that employ styluses or fingers to move cursors, select icons and other items, and even to write on the screen.

But multitouch interfaces are potentially much more versatile. They allow you to use your fingers to manipulate virtual objects on a screen as if they were real, sort of the way Tom Cruise’s character did in the 2002 Steven Spielberg science-fiction film, “Minority Report.” For example, Microsoft’s Surface allows users to rearrange groups of digital photos by just dragging them around on the table top as if they were actual paper prints.

Unlike the touch screens on, say, ATMs, multitouch devices are able to distinguish between the press of a single finger and the press of multiple fingers, and to interpret the motions or gestures you make. They take different actions depending on how many fingers they detect and which gestures a user performs.

On Apple’s MacBook Air, the touchpad still allows you to use one finger to move the cursor and click like a mouse can. But, optionally, it can do much more using multitouch gestures.

You can rotate photos by just touching two fingers to the touchpad and moving the images on the screen as you wish. You can quickly move back and forth through a series of Web pages or photos by “swiping,” or placing three fingers on the touchpad and moving them rapidly sideways. And you can shrink or expand a photo, or zoom in and out on a Web page, by pinching the image.

All recent Mac laptops, not just the new Air, have the optional ability to scroll through a screen without using any button or special zone on the touchpad. You just place two fingers, instead of one, anywhere on the touchpad and drag them across its surface.

In addition to pinching, the new Synaptics touchpads have a feature called “ChiralMotion,” which achieves rapid scrolling by moving two fingers in a circle anywhere on the touchpad. Another Synaptics feature, called Momentum, lets you emulate a trackball by flicking a single finger across the touchpad. This gesture can move an object on screen, like a virtual bowling ball in a game, with the illusion of inertia.

It’s too early to know if the new multitouch approach will ever be as big as the mouse-driven graphical user interface. But it’s already evident that it offers real advantages on devices where a mouse isn’t possible or convenient to use, or the decades-old interface of menus and folders is too cumbersome.

Email me at mossberg@wsj.com. Find all my columns and videos online, free, at the new All Things Digital Web site, http://walt.allthingsd.com.

Companies have failed for many years to produce a successful electronic reader, a dedicated device that would do for books what Apple’s iPod has done for music — allow you to carry around large numbers of titles and enjoy them in a convenient way.

Just a year ago, Sony took another stab at this concept with a product called the Sony Reader. Like the iPod, it was linked to an online store where you could buy thousands of titles that could be downloaded to the Reader. Unlike the iPod, it hasn’t been a hit with consumers, partly because the store was hard to use and had a very limited selection.

Now, the biggest name in online book sales, Amazon.com, is entering the fray with a $400 electronic book reader called Kindle that aims to succeed by offering a much better shopping experience.

The Kindle is the first e-book reader that allows you to select, buy and download titles directly to the device, instead of downloading them to a PC first and then transferring them over. Amazon is offering a large collection of digitized books — about 90,000 — compared with fewer than 25,000 for Sony. The Kindle also can download newspapers, magazines and blogs directly, and update them automatically. This is possible because the Kindle comes with free, built-in wireless Internet access, using a cellular data network.

I’ve been testing the Kindle for about a week, and I love the shopping and downloading experience. But the Kindle device itself is just mediocre. While it has good readability, battery life and storage capacity, both its hardware design and its software user interface are marred by annoying flaws. It is bigger and clunkier to use than the Sony Reader, whose second version has just come out at $300.

Like the Sony, the Amazon reader uses a high-contrast, but low-power, screen technology. The Kindle’s six-inch screen can display only monochrome text and gray images, and there’s lag time and a flash of black every time you turn a page. But I did find that the screen was good enough to make me forget I wasn’t reading the book on paper.

The Kindle holds about 200 titles in its internal memory, and can accept memory cards for storing more books, periodicals and blogs. You can also keep and read some types of personal files and photos on the Kindle, but you have to email them to Amazon for conversion to a proprietary Kindle format.

The battery lasted me a couple of days between charges with the wireless on, longer if I switched it off.

Using the well-organized Kindle store, I was able to purchase books like “Boom!” by Tom Brokaw, “Stone Cold” by David Baldacci and “American Creation” by Joseph Ellis. The process was fast and simple, partly because the Kindle comes preconfigured with your existing Amazon account information.

New releases and bestsellers cost $9.99 each, compared with a typical Amazon price of $15 to $20 for the paper volumes. Prices for other books vary widely, but are generally cheaper than the paper versions.

I also successfully subscribed to electronic editions of The Wall Street Journal, the New York Times, Time magazine, and several blogs and news feeds. This was a much less satisfying experience. The layout of these publications was much clumsier and harder to use than on the Web, and they cost more. Blogs and periodicals that are free on the Web cost anywhere from 99 cents to $14 a month.

The Kindle has some nice software features. It includes a small keyboard that lets you make notes in the margins of books and perform searches. There’s also a built-in dictionary.

But the device is poorly designed. It has huge buttons on both edges for turning pages forward or backward. They are way too easy to press accidentally, so my reading was constantly being interrupted by unwanted page turns. Plus, the buttons are confusing. One called “Back” doesn’t actually move to the previous page, but supposedly to the prior function. I never could predict what it would do.

The “Home” button for returning to the list of content on your Kindle is tiny and located at the very bottom of the keyboard. There is no button to take you to the online store; you have to open a menu and scroll. The book-like cover, intended to protect the device, attaches so weakly that it’s always falling off. And because the power buttons are hidden on the back, reaching around to use them practically guarantees you’ll knock off the cover.

The software interface also is clumsy. There is no way to organize titles into groups or categories, so you have to keep turning pages in the Home area to find a particular item to read. And doing many tasks requires you to scroll a barely visible silver cursor along a narrow side panel.

Also, there is no way to email friends to tell them about books or articles, send excerpts or links, or even buy them a Kindle title as a gift.

Amazon has nailed the electronic-book shopping experience. But it has a lot to learn about designing electronic devices.

Email me at mossberg@wsj.com. Find all my columns and videos online free at the new All Things Digital Web site, http://walt.allthingsd.com.

Corrections & Amplifications

The Amazon Kindle is the first electronic book reader that allows users to download books via wireless broadband, without a PC. This column erroneously said it was the first to allow such direct book downloading via any means. Some early attempts at electronic book readers had built-in wired phone modems for downloading books.