H264 quality differences in players

I am surprised at the significant difference in quality by various players, well to be more precise, VLC & MPlayer. The difference between MPlayer & Quicktime (other than colourspace conversion?) is negligible. For comparing I tried to make sure I use the same frame, which is probably impossible but it seems pretty close and the trends I’ve observed holds true after many tries, QuickTime ~= MPlayer > VLC

Here’s a SD comparison, all 3 players in one screenshot for comparison:

Here’s a scene from 720p content, make sure you view this at 100% (which usually means clicking on the full size image in firefox), first MPlayer:

and then VLC:

and finally, both together for easier comparison. Look especially at the detail on the landing pad and the boat’s surface:

UPDATE: here’s another shot with XBMC (OSX port), looks to be on par with MPlayer (ffmpeg + OpenGL vs Core Video/OpenGL?):