in higher difficulties, the gameplay can be compared very much to the former Race Driver games. the only thing is, that it is much more accessible for newcomers. also, the new AI has a much more realistisc behavior, bad drivers tend to make mistakes, good drivers are hard do overtake and so on. this again makes the game easier for new gamers (you're not competing against "perfect drivers" but a grid of different skilled drivers) and more interesting to skilled players. as ever, you can chose to disable all driving helps (traction control etc).
also, this is no PGR! there are city racetracks no, but it is still motorsport. you're driving in licensed sport cars, not in production cars. you're driving on a number of various licensed tracks (Nürburgring, Spa, Le Mans 24hs, Istanbul....) and a number of fantasy creations (some "classic" racetracks, some city tracks...). but the important thing is, it still feels much like a motorsport game, only with a really stylish, cool presentation that also appeals to the PGR / NFS gamer. Best of both worlds, really.
Again, just wait for the demo and believe in the game. I mean, you have to admit that everything looks really great and promising so far. Just have faith and give it a try as soon as you can get hands on
And it least here in Germany press is praising Grid as contender to be the best racing game ever. And German press is known to be very critical, especially when it comes to arcade racers.