I'll second PMS (hurr hurr).
After following guides to get different renderers/transcoders going to play pretty much anything, the only negative that I've found with it is upgrading. A lot of the times, an upgrade to the software will result in previously playable files becoming unreadable by the PS3.
So I've stuck with the old saying, "If it ain't broke, don't fix it." You find a version that works, and stick with it.