I've been playing Shift 2 for the last 2 days, and have kind of gotten the hang of it. The physics really threw me off at first, being so used to GT5. Now, I'm racing much better and finally enjoying the game rather than getting irritated with so many race restarts.
The best part of the physics in the game is the crashing. The damage models are awesome too. I was going into a turn too fast in my 240sx yesterday while drifting

and flew off into the sand and my car started flipping, and was totaled . I tried to get back on track with 1 wheel still left on, hehe. When you lose control in Shift 2, you actually fear the consequences of your carelessness. In GT5, 'heh, that 200mph dent will pop out, it's all good.'
Shift 2 is a blast, but I'm sure will die down for me, and I'll be back to GT5 soon enough.
Helmet cam is also incredible but its weird in that you have to kinda turn as soon as the driver rotates his head rather than where you may normally expect to with a front on view. Once sussed out its cool though.
I like that view, but really can't use it while racing. When I first started playing the game, for some reason, it gave me a false sense that my car was starting to turn, so I would actually start my turning a little late and fly off the track.
I've been sticking to the hood cam for the most part doing career races, but when I play around, I'll sometimes use the helmet cam.