On any platform, I would recommend Test Drive Unlimited 2 personally. A lot of people seem to dislike it but I found it a lot of fun, it's vast and truly free roam (unlike Forza Horizon which fools you into thinking it is).
I just downloaded demos of Crash Time 4 and 5 on xbox 360 since Neema mentioned them in his Steam sale thread, just had a crack at 4 and it's OK I guess but the physics are a bit weird. The cars turn far too quickly and it suffers from the age-old indestructible car syndrome whereby you barrel through practically every lamppost, road sign and most other cars in sight. It's therefore pretty much a modern take on Midtown Madness, and hardly progressive.
Also the voice acting is painful, not so much bad (some of it is lost in translation I think) but there is too much of it and it can get really tedious. Add to that the action freezing countless times for the game to give you written tips and things get really clunky. I encountered a couple of bugs too where I crashed in to other vehicles and became locked to them, though perhaps that is realism!
Fun for a couple of quid though, but not much of an advance on something like Need For Speed World, which is effectively free.
TDU and TDU 2 for the win, for me anyway. Though I would love a free roam driving game with proper physics, and was hoping for this with Forza Horizon. Why they didn't keep the Forza 4 physics fully intact (and it's really not, despite some misleading reviews out there) is beyond me
EDIT: Burnout Paradise is fun too, like Crash Time but, umm, fun. But very much not a sim. I was lucky enough to get it as one of Sony's "our bad" presents when they had all that data hacked, but must admit i've only played it once. It's just a bit too lightweight and arcadey for me. Hooning around in GTA is almost as much fun, with much more of a game around it.
