> In short, though: More support for formats to be decoded, best HW acceleration available as open source, much less hacks in there compared to FFDShow-tryouts, uses vanilla-based ffmpeg libraries instead of the mess that is in FFDShow-tryouts, as well as LAV Filters just being still in active development compared to FFDShow-tryouts being dead.
FFDShow still offers more extensive video/audio postprocessing options over LAV Filters, but most people are probably not even aware that they even exist.
Anyway, personally I would highly recommend using CCCP if you're on Windows - it doesn't ship with any useless extras (like most codec packs you might find on the internet) and is pre-configured to maximize compatibility and playback quality - you get better quality than VLC will offer, for example. And if you throw madVR on top of that you can make it even better with top of the line rendering and scaling (though the difference isn't admittedly that big).
[1] http://www.cccp-project.net/forums/index.php?topic=6677.msg4...
If you're on OS X or some *nix and want a simple video playback solution you're better off using VLC, though. For advanced users, there's mpv.