People today use the Netflix service on their computers, but Netflix (NFLX) has cut a series of deals with hardware partners to make the service available on TV sets through an array of devices.

Most of these devices were designed to do other things: a videogame console, high-definition Blu-ray disc players, a TiVo (TIVO) digital video recorder. So to see how well the service works on these devices, I’ve spent the past couple of weeks comparing the Netflix experience on Microsoft’s (MSFT) Xbox 360 game console, on LG Electronics’ BD300 Blu-ray disc player and on a set-top box from Roku called the Netflix Player. The last, as the name implies, is designed mainly for Netflix service.

The devices suffer from a relatively skimpy selection of videos on the Netflix Internet service. Netflix has more than 100,000 titles for rent on disc, but about 12,000 titles for viewing through its Internet service at the moment, and there’s often a months-long delay after a movie’s release before it shows up online. Television shows generally turn up more quickly, with a handful, like NBC’s “Heroes,” watchable the day after they air.

Still, I find the Netflix service very appealing, especially for catching up on episodes of TV series, such as “30 Rock,” that I missed when they aired. Unlike the iTunes Store and other sites that charge users $1.99 per TV episode and $3.99 to rent a movie online, the Netflix Internet service is free to subscribers to its DVD service on one of the company’s “unlimited” rental plans, which start at $8.99 a month.

Depending on how fast your Internet connection is, Netflix videos begin playing almost instantly, though you can’t keep permanent copies.

Connecting the devices to Netflix through my wired home network was easy in all three cases. I used a wireless home network — more common in homes than the wired variety — with the Roku device, the only one of three products that comes with built-in Wi-Fi (it worked well in this mode). People who want to use the Xbox 360 with a wireless network will have to spend $70 or so on an external Wi-Fi adapter. LG recommends people use only a wired home network to connect to Netflix from its player, including adapter kits that cost about $100 for transmitting data over home power lines.

All the devices require you to create a list of movies you want to watch from a computer, just like Netflix subscribers set up “queues” of DVDs to be delivered by mail. The Xbox 360 offered by far the most elegant-looking interface for browsing through videos in my Netflix queue, letting me glide through a long row of cover art representing the movies and TV shows I selected on my PC.

In contrast, the Netflix menu on the LG Blu-ray player and Roku device were more static, making it more awkward to navigate the expanse of titles. Netflix became available on the Xbox 360 in November as part of a more sweeping software upgrade, delivered over the Internet, that remade the graphical look of the system.

The quality of most of the videos on Netflix is, to my eyes, about DVD quality, though Netflix is adding some titles in high-definition to its Internet library. HD titles were available for viewing only through the Xbox 360 when I was testing the service. Roku and LG say they will make software updates available online this month that add HD support to their devices.

The Xbox 360 also has some annoying quirks when using it as a movie player — including a noisy fan I found distracting. The game controller that comes with the Xbox 360 is clunky for playing movies, so users will need to invest in an inexpensive additional remote-control design for media. The Roku and LG players, in contrast, were totally silent and had acceptable remote controls for watching Netflix videos.

I experienced the most serious glitches with the LG Blu-ray player, which occasionally dropped the video signal to my television set as I was watching a movie. LG says the loss of video signal could have been due to the connection I used to hook the player to my TV, though I’ve never had a problem with other devices using the same connection. The LG Blu-ray player also took the longest of all the devices to install software upgrades from the Internet.

While there are some differences in the Netflix experience on the Roku device, Xbox 360 and LG Blu-ray player, none of them is so great that they should trump other considerations — like a desire to play videogames or watch HD Blu-ray movies — in deciding which system is the best fit.

The LG Blu-ray player is available online for about $300. The cheapest Xbox 360 model is $199. (To get Netflix through the Xbox 360, users must be “gold” members to the $49.99-a-year Xbox Live game service.) But if what you’re after is primarily Netflix movies, and you’ve got room near your TV for another box, the $99.99 Roku product is the best value.

Walt Mossberg is on vacation.

Write to Nick Wingfield at nick.wingfield@wsj.com

Now, two more set-top boxes have been launched to try to marry the Internet and the TV. Both adapters, from Sony (SNE) and Roku, worked well in my tests, but each has limitations. The problem is that one of the boxes supplies content from a wide range of Internet video sources, but only works on selected models of one brand of TV set; the other works on a wide variety of TVs, but only provides a single source of content.

Sony’s adapter is the Bravia Internet Video Link. This is a $300 module that attaches to certain Sony HDTV models. It can either be set up beside the TV or snapped onto the back of the set. Once it’s connected to your TV and to your home network for Internet access, a new menu appears on the TV allowing you a choice of videos from numerous online sources, including YouTube, Yahoo (YHOO), Blip. TV, Sports Illustrated, AOL, Wired, and the Web sites of CBS (CBS), Showtime and more.

Setting up the Bravia Internet Video Link was straightforward, even though it involved a welter of cables. There is no built-in Wi-Fi — you need either a cable or an add-on wireless adapter to connect to the Internet. The primary hookup to the TV is via a modern type of cable called HDMI, for High Definition Multimedia Interface.

I tested the Sony Link using the company’s most unusual HDTV set — a tiny, very costly model that uses a very thin, very vivid new screen technology called OLED, for Organic Light-Emitting Diode. This TV provided a spectacular picture, but it isn’t required to use the Sony module. The Link works on many larger, more common Sony sets with more common screens. It just doesn’t work on non-Sony TV sets.

Sony’s Bravia Internet Video Link adapter

The Sony module doesn’t have its own remote control. It uses the one that came with the TV. This makes for an awkward experience, because there are no standard play and pause buttons, and various other buttons on the remote meant to do one thing on the TV may do another when watching Internet video via the Link module.

Also, I found some of the Internet content to be disappointing. Many of the items labeled “movies” on various Internet channels were really just trailers, and some content was stale. For instance, some baseball news videos on Yahoo were weeks old.

However, Sony plans to make one of its feature films, “Hancock,” available through the Link module before it’s released on DVD. More important, it will be adding access to Amazon’s (AMZN) forthcoming video-streaming service, which promises to contain a wealth of full-length content.

The Netflix Player by Roku is much simpler. In fact, it was the simplest set-top box I have ever tested. It costs just $100 and does just one thing: It allows Netflix (NFLX) subscribers to view its movies and TV shows via the Internet on a television set instead of on a computer. It can’t get you any other video content from the Internet.

The Netflix player is a small, plain black box that works with most TVs, not just digital or high-definition models. It connects using both old-fashioned cables, like the kind used by many VCRs and older DVD players, or an HDMI cable.

Unlike the Sony, the Roku box includes both wireless and wired Internet connectivity, and has its own remote. While the box is capable of displaying high-definition content, the Netflix service isn’t currently streaming movies and TV shows in high definition, so you get varying quality, depending on your TV and Internet speed, up to DVD-type levels.

There’s no added monthly fee required to use the Roku box, but you must be a Netflix subscriber. The box merely displays the movies or TV shows you have placed in your Instant Queue on Netflix. You have to do this on your computer before viewing the videos on the Roku box. You can choose from around 12,000 streaming movies and TV shows, far fewer than the 100,000 titles Netflix makes available via DVD, but a sizable collection.

In my tests, the Roku box set up quickly and easily, the interface and remote were simple and effective, and the movies and TV shows I tested streamed quickly and without hesitation over my fast home Internet connection.

Both products are meant to promote sales of other things — Sony TVs and the Netflix movie-rental service. They do these tasks well, but neither is the breakthrough solution that will connect most TVs to most Internet video content.

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.