Anyway, downloaded the demo... and it was a pleasant surprise. It's actually not crap. The graphics look great... surprisingly it's close to the original teaser trailer which was thought to be CG. Everything is very clean, there's not a bunch of jaggies like Carbon. The smoke effects are top notch, by far the best I've seen this gen. Framerate is completely steady (finally!), the physics seem solid and the damage system is pretty good as well. Zipping past a car flipping over and over again at 170MPH is a really nice feeling... and going on to do the flipping yourself if you make a mistake makes it even more sweet.
As for gameplay, it's pretty fun as well, but it's Need for Speed. It seems less annoying to play for whatever reason, but IMO it's fun. If you thought Carbon and Most Wanted's gameplay were good, you'll like ProStreet. If you hated it, you're probably not going to like it.
Overall, it's a good surprise for me, considering I thought it'd suck. I don't think I'll buy it though. Maybe I'll pick it up when it's cheap.