Downhill Jam is not a good game, but is not a bad one either. Just not consider it as a REAL Tony Hawk game.
Other bad thing is than Tony Hawk is the only pro. The other caracters are fake, but his own personality fixed a little that. And you still can create your own skater.
And the soundtrack? Don't worry, is still as good as the past games. So, just giving a 5.9 to this game doesn't seems to be fair to me, but this game doesn't deserve more than a 7.0 either. So, since Undeground 2, than in my opinion I consider it the "last great Tony Hawk game", i as been waiting for some new TH game being super good, and Downhill Jam...well...doesn't....
So now my hopes are in Proving Ground, that I think, will be the last Tony Hawk game on the PS2. Downhill Jam is still being a good game, but not a "good Tony Hawk game". There is a big diference... It just I don't consider this game a truly Tony Hawk game. My advise to you: rent it if you want, and make your own choice. There nothing more I can do.