The PC version is obviously better, but the difference is pretty much image quality and framerate. PS3 version runs at a solid 30 and features great 720p image quality. PC version is obviously above this, but the PS3 version is very respectable. I was playing with a buddy on my PS3 while he was using his PC and the PS3 version was actually loading faster than his PC (though my PC loads twice as fast as PS3).
Unfortunately, Source engine games tend to exhibit slightly jerky mouse movement on my system. Not sure why, but it looks bad. The framerate is a solid 60 fps and it looks perfect when I use a 360 pad, but looking around with the mouse is much less smooth. I doubt most would notice it, but it definitely bothers me. :\