I liked the demo too, but I really don't know if I want the full version or not because there's so little rally in it. I'm not interested in the buggy races and desert rallies are probably my least favorite rallies after tarmac rallies that lead through too much (sub-)urban areas.
It's a lot better than Dirt1 because the physics in Dirt1 are just broken. Not too arcade or anything, but simply broken. In Dirt2 they are at least good for an arcade game. It's almost a throwback to Rallisport Challenge 2, which used to be my favorite racing game.
So if it was just about the gameplay (and the graphics! Because those are excellent. Cockpit view is stunning) I would get it in a heartbeat, but there is just so little rally content for me that makes me worried about dropping so much money on it.
I might get it when it gets cheaper.
I really hope a good rally game comes along soon. I don't even care if it's realistic or arcade style as long as it has a good vibe and plays well.
Too bad Rallisport Challenge 2 isn't backwards compatible on the 360. It would still be the best rally game on the platform and one of the best racing games in general too.