Spent a ton of time playing this on my vita, and while it was really impressive at first, my opinion has soured pretty significantly. The single player just isn't any fun once you've maxed out several cars and seen everything the city has to offer. It's pure repetition from then on out.
The crashes, a huge part of the game, are boring as hell. Half the time I crash into a wall going 130+ mph and the car just stops dead, with a lackluster generic crash sound accompanying it. There's zero wow factor.
Too many things about the game are too slow. Once you show me that opening cinematic for a race once, just skip it from then on out. It's not interesting to watch, and I've even come across a few that are unskippable and have to play from start to finish every time you retry a race. Loading times between retries are also quite long, but that could just be because of the Vita.
And I've come across some infuriating bugs. Speed runs are some of the toughest races to beat because you pretty much have to be perfect. Well on one of them the target is 125 mph, and I just barely got there, 125.0 mph exactly. Didn't register as a 1st place win. Rage.
Overall I'm still happy with the game because it's one of the better Vita games out there right now, but damn does it have some real wrinkles.