Project Torque

I played it. It goes like this:

0 - 4 hours gametime: boring, wtf, no skill, where are teh physics?!
4 - 24 hours gametime: über, kewl, love it, omg omg moar
24 - 28 hours gametime: no not this thing again! aaargh.

Starts out boring, becomes fun, becomes boring. It's just the same thing over and over again.

Physics and game-play wise, how does it compare to any of the NFS or GT games?

In my opinion both NFS and PT have wierd physics. Dunno about GT, but it seriously isn't as realistic as for example Gran Turismo (PlayStation series). If you want something new try it, but it takes some time to get used to.