[JohnnyCanuck]

There's no problem using a WHS to stream to an ATV. I use XBMC. But ... the ATV does not have the horsepower to play 720p or better .mkv files. The ATV is not in the league of a PS3 using PS3 Media Server. Yes, the interface is better, but the video quality isn't.

 

[JohnnyCanuck]

I have read about that mod and haven't tried it because I just don't think that, even with the mod, the video performance of an ATV measures up to the PS3 (although it might be worth playing with to see ...).