PvP is significantly worse because of hackers. They can do far more than hex editing is capable of, including speed mods, infinite health and stamina and more!
Well that makes sense. Bit of a shame really, I know the framerate is supposed to be a lot nicer but I don't think I can be bothered shelling out £25 for 30 frames.
Really, though, I can't tell you much about PVP, since I'm just trying to get through the single player as fast as possible, then move on to DaS2. I'll be getting that on the PC, too, just for the fact that it's easier to implement mods for it.
And to answer your question, PC version has a mod that allows you to go to 60 fps. Sounds like you've heard of it. The DLC is also part of the package.