I have spent the last 3 days getting to know my new appleTV. This much awaited little appliance just arrived on Friday 3/23 at the apple store on Fifth avenue. I was there for a macbook repair and picked one up to try. I wanted to share my impressions/ surprises/realizations with you all....
setup was easy, although it comes with NO connection cables. Also, it only supports widescreen monitors or TVs. Also, surprisingly, there is no supported adapter for connecting an apple cinema display with its built-in dvi cable to the device.
Anyway, on the plus side, the toslink output is not a mini toslink like Airport express or mac mini, and there is separate analog audio out (havent tried it yet). The sound (so far) is great. i dont notice any difference over the AEX digital output (I have everything in Apple Lossless, going to paradisea dac via glass toslink, then signature 30 to omega super 3 hemps). Apart from the obvious advantages of having the visual interface for your music as compared to the AEX, there is the additional advantage of being able to control your digital media independently of the main computer. {Yes I could do that before by controlling the speakers with my laptop). One notable downside to this is that the appleTV will not appear on the remote speaker list of iTunes and thus will not play simultaneously with other speaker set-ups in the house. I have 3 other AEX stations which will play in unison, the bedroom system is now off that circuit. Also, I have yet to fully understand/realize the potential of the internal harddrive. The device will comfortably access all your media on your computer and connected drives, so why have an internal drive which is the most likely part to go bad? Perhaps for purchasing purposes?? Perhaps to house the Mac OSX which the system is built around. Anyway, when seting up it automatically asks you which iTunes (library) you want to sync with. It took me a while to realize that "sync" means copy all files. a little bit of exploring in iTunes preferences and the appleTV device settings (on iTunes) fixed that. I now have close to nothing on the harddrive, just some photo albums for the screen saver.
An alternative to appleTV may well be a dedicated mac Mini. You get a bult in dvd drive, larger harddrive and a full fledged computer, similar Front Row interface, same remote, but no 811.n streaming (mine is connected by ethernet cable anyway) . Used they go for $400ish.