I have it, and there really aren't any FPS issues. The issues are mainly common on people with weaker computers, yours should run it flawlessly.
FPS issues would be extremely apparent in that game. I had it before I had this computer so I have ran it on a slower computer, and this is the kind of game that is kind of difficult at anything below 60fps. Mainly because any stutter throws off the rhythm, and if you are in the middle of a huge combo it can get very annoying. But since I have put it on my current computer I have never seen it go below 60fps, and I have recommended it on PC over any console since.
If you don't have, and don't plan on getting any consoles you should try it on the PC. It's a very fun game. Plus the PC makes it very
easy to get custom songs running on it, which makes it even better.
Edit: I run it at 1680x1050 with all (both) settings maxed. Forcing AA through ATi's CCC makes the fretboard disappear, and there's no in game option for AA, so it's off. Stays 60fps at all times, except when I'm recording with FRAPS. In which case I turn the resolution down since youtube downscales it anyways and i get my 60fps back