Have been using the Apple TV 2nd gen. 2010 for a while, here is what my experience..
I suggest the ATV is just like iProducts, yet another i-Product that Apple didn’t spend/have enough time to test it before the product launch.
1/. Since it only has optical audio output (no 3.5mm nor composite Audio), all audio related output will depend on HDMI port, there is NO WAY of turning off the display when streaming Audio from the iTunes. (for whatsoever reason, power save, screen life etc…), there is only screensaver function on ATV, no screen off after a period, and you cannot turn off the display device either because the Audio output depends on that.
2/. I am having a problem with Audio volume that some of the Movie/Youtube clips/Movie Trailers have different Audio level, there is no normalizer, and basically no way of changing them with the ATV remote, you just cannot expect users to put the ATV Remote down and get yet another remote to do simple volume up/down/mute right?
3/. Video streaming is as raw as can be, I know iTunes only do MP4s, but no SRT/SUB support on streaming like all other player, example AirVideo on i-Devices.
4/. iTunes really needs more work to get better user experiences for user to enjoy ATV, I know iTunes is as suck as before, but at least can Apple please get their focus back to the basic functions instead of dreaming to get a piece of social networking pie? (Ping? we already has Twitter, Buzz, Facebook….chomp 2^1024 other open options.)
Still, I think ATV is a very good idea, well designed piece of hardware, I am sure if Jailbreak communities get more progress or Apple gets the AppStore for it (if ever) we should be able to do way more cool functions on this cool little box.