Good, could have been great (from a diehard fan's perspective)
First off, I make it a personal rule to accept any movie for what it is and judge it as such. I don't dwell on what should have been done differently, usually. This movie is one of the exceptions to the rule. Yes, Tony Scott, Jerry Bruckheimer, Don Simpson, and company were trying to make a Hollywood-ed up version of NASCAR stock car racing and for better or worse they essentially succeeded. It was Hollywood-ed up and taken for what it is, it's a great movie.
From the perspective of a die-hard fan, though, it could have been even greater but for a handful of details. Of course one of the main gripes is the shifting gears once already in high gear. I know they had to illustrate him "dropping the hammer" and showing what he really had, but still. Also the beating and banging at Daytona that left Cole and Russ' cars in shambles was ridiculous. A little door rubbing, yes, but I've been watching racing for over 20 years and that was not rubbing. That was trying to knock the hell out of one another. Neither car would have been remotely competitive, much less in contention to win, after even a couple of those encounters, leastwise not without some repair work in the pits and a caution flag to get caught up.
Cary Elwes's dialogue as Russ Wheeler was likewise beyond over-the-top and reached ridiculous levels. I get that they were trying to create the image of a villain, but in reality NASCAR would have black flagged his ass quicker than you can say Nicole Kidman's leg had he declared before the race and then said on the radio that he was going to intentionally put Cole in the wall and then did it. Could have been easily rectified had they simply had him play nice for the cameras and then tell his crew he would wreck Cole, then have him do it on the track without saying he was going to on the radio.
Most everything else I was satisfied with. I enjoyed the character development, the relationships between Cole and Claire/Harry/Rowdy, and the sounds of the cars along with Zimmer's score was pure perfection. Just a few things gnawed at me that keep this from being a better movie.