I'll preface this post with fact that I am an A/V enthusiast 1st and foremost...quality over flexibility/versatility...ok...
After nearly a year with a jailbroken aTV2 running FireCore's own aTV Flash (black), Plex, etc. I decided it was time to finally put the new 1080p aTV3 against the very versatile (at least once jailbroken) 720p aTV2. My tests were somewhat alarming...as I expected the two devices to output similar video quality when handling the same files. My tests (at least for me) sealed it...there was no longer a place for the aTV2 in my A/V setup. Anyone looking to buy an overpriced aTV2 on eBay should seriously think twice. With a little more effort (and the gear to support it)...you will be streaming much better quality video to your HDTV.
I tested Handbrake encodes (using aTV2 and aTV3 presets). I tested various applications (including MP4tools) where the resulting files weren't re-encoded but re-muxed. I tested using AirPlay mirroring (Mountain Lion), Plex app, aTV Flash's own Media app (which by far outputs the worst quality video). I tested both 720p and 1080p encodes...the list goes on and on...
Long story short, every time, the aTV2 was shockingly weak at outputting clear, clean, well defined image. All it meant was spending a few extra minutes/hours and some computer processing power to re-encode or re-mux the files I wanted to watch on the aTV3 using iTunes as a bridge. In my opinion...worth the time/effort.
I really appreciated my time using my jailbroken aTV2 (with aTV Flash installed) and look forward to the time when the aTV3 will be a bit more useful once jailbroken. But until such time...the $99 aTV3 wins! See you later FireCore.
Ps. I sold my aTV2 for over $300 last week
Also, there will be lots of you who will say, ya but the aTV3 can't do this or it can't do that...and this may be true. However, if you are looking for the best possible video feeding your HDTV, do yourself a favor and sell your aTV2...now!