I can tell you I have the game. It's pretty fun especially the party mode but there are a lot of glitches and bugs.
The online servers are laggy and if you save your franchise mode, the next time you play it you cannot load it.
Also theres pass interference glitches and the blurry zoom in camera glitch if you press the button after you select a play.
If you can handle the glitches, go ahead and buy it. It runs smooth at 60fps and the superstar is a great mode that works for me.

Above I'm a proud Gran Turismo fan, not a Sony fanboy, and now a proud 360 owner, but sharing xbox live accts ATM
End of 2009 Predictions (made Jan 1, 2009): My predictions were pretty accurate, the 360 was over and the Wii was just under.
Wii: 65 mil (yea I'm crazy) 360: 35 mil (its getting there) PS3: 30 mil (the slim better do well)
End of 2010 Predictions (made Jan 7, 2010):
Wii: 81 mil 360: 47 mil PS3: 45 mil