Got a few hours in this-morning, here's what I think so far.
First thing you notice are the graphics, they are fantastic, stunning at times. The amount of detail is incredible, each blade of grass is rendered and sways in the wind, obstacles move when you hit them (for example when you hit a tyre wall, it brakes up and the individual tyres scatter), crash barriers deform. Talking of crashes, the damage model is fantastic, you really 'feel' the impacts in the cockpit veiw with the windscreen shattering etc.
The crashes look particularly great in the replays, with bodywork bending and individual pieces of glass flying everywhere. The lighting and shadowing looks gorgeous too. One thing some people might not like is the fact that everything has a kind of golden tinge to it, like there is some arty-farty filter on the 'camera'. I like it, but it wont be to everybody's taste.
There is a downside to the stunning looks though, and that is the fact that they run at 30 fps, as opposed to the 60 fps of Forza 2. It's nice and smooth for the most part, but it does sometimes get choppy/jerky when there are lots of cars on screen. When that happens you really long for the liquid smooth framerate of Forza.
It's annoying because 30 fps would have been fine if it never dipped below that, but I'd say it definately drops below 20 at times
And the handling?
The Buggys, ORR pick-ups and 'Rally Raid' trucks are lots of bouncy, big-jump, sideways fun. Seriously, they are a blast, and a nice diversion from the track driving of Forza.
As for the rally cars, I can only describe the handling as a bit strange. The lower powered cars just dont feel anywhere near loose enough, and the brakes just tend to stop you instantly rather than help you get into a slide.
Things get better with the Scoobs and Evos, the higher power helping them act a bit more loose. Tweaking the setup helps a lot too, but that strange brake behavior is still there.
Overall the rally cars aren't unplayably crap, but they should have been a lot better. Problem is you have to do rally events to progress in the carreer and unlock better cars and tracks.
All in all I'd say it's probably worth getting for the buggys/ORR pickups/Rally Raid trucks alone as they are great fun, just think of the actual rally cars as a mildly entertaining way to unlock more cars and tracks for the other modes.
Oh, and multiplayer support is almost non existant, you can't actually race against anyone over live, all you can do is a rally tryig to beat the other players times. You dont actually see their cars on your screen. Utterly gay, because a multiplayer Live game with the Buggys would have rocked.
So it depends how much you personally care about such things.
I like this game and would rate it above Forza, It does have that one more go appeal 