Ok, now my thoughts about the game...
To sum it up first: I think it's a worthy successor of NFSU better in every aspect.
Now to go to the details.
RACING
I must say that I was very impressed with NFSU's arcade racing style. If NFSU was fast, this is faster! The game friggin flies!
Physics are a tiny bit more realistic than in NFSU, so you'll notice the difference between a FWD and a RWD car, but they're still arcade enough that it won't take away the fun.
Ultra high speed, nitro graphics effect and very nice tracks make an unforgettable experience! This is especially good on tracks with long straights and maybe there's a little bit too few of such tracks.
There is one important thing I have to say: if you prefer sim-styled games, stay away of this as you will be disappointed.
The only drawback when it comes to drive style is the wallriding - going through a corner on the outer side and sliding on the wall is something that takes away the challenge. It's really annoying with the 90 or more degree turns.
If you thought NFSU was tough, NFSU2 is too easy! I must say that the AI opponents are too slow and not challenging enough. In most of the races, especially URL, it'll take you half a lap to get to the first place and then have a constant 1-2 second lead throughout the lap. This might make URL races boring as there's no traffic.
TUNING
If NFSU had a lot of parts, NFSU2 has 2,3 even 4 times as many! You will find all parts from NFSU and a whole bunch of new ones!
If you like to style your car, you'll spend a lot of time in the car customization screens. The options are unlimited!
CAREER
Career is imo a thing that was not done as good as it should. Too many races and not enough story. There's a total of 10 maybe 15 cutscenes with very little dialogues. The storyboard was about 3 lines long.
Free roam is an excellent addition, but there is a chance you'll get tired of it soon <-- this will happen if you don't like the driving style. Once again, if you're a sim lover, the free roam will turn out to be a pain in the behind.
The shops may turn out to be a bit hard to find, but there's enough of them available in the city.
Outruns are another thing that could've been done better. Especially when you have a lvl2 or lower car it's pretty hard to win because of the famous catch up. It might take up to 5 min to win an outrun event.
RACES
About the races: there's plenty available and you have a wide selection but in the end you'll have to do races from each game mode. What can't be left out are the URL races and the circuit. URL is usually pretty good, but unfortunatly there are only 2 locations: airport and racetrack. You'll have to do around 30 URL races and to race on 2 different tracks with a few variations can soon become boring. Circuit on the other hand varies from great races to terrible races. There are one or two races that will last for 10 min. Most of them are around 5, 6 min.
Drag is ok, but imo there are a few straight open tracks missing.
StreetX is a very nice addition!
Drift is same as in NFSU, maybe a bit easier. Still one of the great modes.
StreetX is circuit racing on drift tracks. Quick sharp turns, very good!
Downhill drift will take quite a lot of getting used to, it might be a bit hard. but turns out to be a nice addition as well.
Sprint is basically the same as in NFSU. Some longer sprint don't take away the fun.
So in conclusion.
I like NFSU2 very much! As much as I liked NFSU when it was fresh.
When comparing I must also say that the NFSU2 is a big improvement!
) and nfsu, nfsu is far more realistic than burnout. 
