Ok, impressions:
I messed around with the game for a couple hours last night. I started out by turning off all of the assists and going to Bristol to run some practice laps. I really, really like the way the cars handle so far. It's not pure sim handling, but it's close enough for me, especially since I was playing with a controller.
I spent the bulk of my time after that painting my car. The paint booth needs some work. I am hoping you unlock more sponsor decals or something, because as it is there are not enough pre-made ones. When you cycle through your existing layers in the menu, it does not highlight the corresponding layer on the car, making it extremely difficult to figure out which layer you are about to edit. Also, cycling though those layers is way too slow, and I only had 30 or so (out of a possible 1000). And probably worst of all, when creating a new paint scheme the car has no headlight, tail light, grill, make or model decals on the car, and I can find no way to add them. I was able to make a cool unsponsored car for myself, complete with yellow stripes on the bumper, but it looks kind of dumb without the "car" decals. I took pictures of the car, which I'd love to share, but I couldn't find anyway to get the photos off of the xbox.
Once I was done with my car I ran a 15 lap race at Charlotte on medium difficulty and with a controller. I qualified 7th and took the lead pretty quick, but around lap 11 or so the first few guys ran me down and passed me. I think this might be because I slapped the wall a time or two and hurt my car, which is actually pretty awesome. After the race I wasn't satisfied with how I was running the track so I hooked up my steering wheel and turned some practice laps. I definitely prefer driving with a wheel, except I was getting a weird problem on the straightaways where the force feedback would start jerking the wheel back and forth, light at first and then more and more until I spun out. I was getting off of the turns fine, so I don't think I was causing it myself. Afterwards I started easing on the gas more slowly and it seemed to not happen quite as often. I turned force feedback off for awhile and I ran fine, so I think this might be a bug. That aside, after 30 minutes or so of turning laps and tweaking some basic setup stuff I was able to really improve my times, which was cool.
Anyway, my general impressions of the game are actually pretty good. I ran into bugs like I mentioned, but not as much everyone else since I only did one short race and I haven't played online. The most important thing to me was that the cars drive well and they seem to, so if they can patch the bugs out later I am fine with that. I'm going to run some more single races tonight and then hopefully start career mode. I don't want to jump online until I am confident I can hold my line around other cars in the corners better.