This is virtually irrelevant unless you're even more anal than I am about video and audio quality...in which case, the ATV2 is not what you're going to use to satisfy your fidelity addiction. I use the ATV2 for convenience. When I want to get my money's worth out of my theater, it's Bluray or nothing (many blurays are even disappointing and over-mastered, imo).
These devices take an excellent source (such as the best blurays on the market) and clean them up a bit to avoid showing artifacts on 100"+ screens. Unless you have a $15k+ projector on a $5k+ screen that's 100"+, there's virtually no way you'll notice any difference.
I promise...take it from an audiophile nutjob.
Thanks for the insightful reply. What you are saying makes perfect sense; especially with high quality sources, like carefully mastered Blu-rays.
However, I have been impressed by the PQ differences with lower quality material on different devices.
I also use ATV for convenience and have been archiving my large DVD collection for use throughout the house (multiple ATV2s and Apple MacBooks that my family all use to watch stuff on the "Eco-System").
Recently, I bought a low-end Blu-ray player (Sony BDP-S580) and was impressed at the difference in PQ when watching Netflix on the ATV 2. This was a surprise for me, but watching the same program material, connected to the same network, AVR and TV, both via HDMI (even the same cable brand) produced a noticable difference - for me, anyway. HD shows on Netflix are subpar, at best, which prompted me to run some other experiments. For example, playing back my M4Vs on the same player produced a different video experience than on the ATV 2 (I am carefully bypassing which one was better )
The biggest surprise for me, however, was how different my ATV 2 videos look on different display panels; one of my ATV 2s is connected to a 5000 series Samsung LED and another one to a cheaper panel. I was not expecting the night-and-day difference I saw with compressed SD content from ATV 2, since I watch Blu-rays on these panels and they both look fantastic.
So, for SD content (especially compressed h.264 video), I really do wonder if something like ABT, Marvell or HQV processing would produce differences similar to what I describe above.