I've played it. It's good, but not great. In a nutshell, the racing is OK but the game is lacking in features. It sorely needs some sort of online league. On launch day (late afternoon IIRC) there were only a handful of people online, mostly in private servers I believe.

They have been good at adding DLC (paint schemes and additional spotters) with some premium and some free. I didn't play enough of the career mode to weigh in on it and found the challenges more difficult than I thought they should be.

If you get it for $20 or so, I'd recommend it but not more than that. Not a bad game, but just needs more.