The device went on sale this week, and various reviews have popped up since. Cnet gives some insight on the product, calling it an elegant solution, and streamlined setup. PC World says the device "just plain works." Nevertheless I see some major shortcomings with the Apple TV. Some of which can be overcome in the near future, like the lack of HD-quality content available from the iTunes store.
The Apple TV is not for everyone though, as you are tied to the iTunes store for all streaming content. This is something Apple might be reluctant to change but would make the device far more useful to a larger crowd. Also despite the wide range of connectivity options at the back of the small device, composite and S-video jacks are absent, so if your TV can't support a 480p wide-screen image or better, you can't use the Apple TV.