There appear to be two separate problems: People simply getting low fps, and those getting similar framarates, but far worse actual performance. Vsync may slightly help the former (though it's really just replacing the whole screen being a frame behind with only part of the screen being a frame behind due to tearing), but has little/no effect for the later.
In addition to this, I think there is a massive issue with relativity here.
Some people say the game doesn't run well, and mean it runs under 30fps. Others say the same, but it runs at 50+fps and dips under 30.
Some people say the game runs just fine, and mean the game runs over 30fps. Others say the same, but it runs over 50fps.
So you see, unless people put their average and average min frames, just saying "it runs" or "it runs poorly" doesn't help the issue at hand.
On a totally different tangent, do other people's menu run at strange rates? When in normal mode, my menu's will run at 45fps almost no matter what the fps was before I went into the menu. Additionally, Enhanced and Premium run at 35 and 25 respectively. AA(off, 4x, 8x) doesn't change the frames/second.
