Recommended video file specs

I have a collection of video files I use on another media server. It has more power than my stock AppleTV so it has no problems with these files (like stuttering issues). When my AppleTV was running the stock OS, I used the Apple support site guide to determine what files the AppleTV could handle. Now that I’m running ATVFlash, I’m using Nito to watch movies. Now I have a larger group of video formats I can watch, but some files don’t stream well over the hard-wire 100mbit connection. Is there a guide that has the suggested data rates for the different file types that ATVFlash supports. Does it change with the software you use, Nito vs. XBMC?

Regards.

Maximum video resolution: 1280x720 @ 24fps, 960x540 @ 30fps, up to 5 Mbps bitrate