ProStreet is a monotonous racing game with some serious issues.
The Bad: Annoying announcer, monotonous races, unbalanced throughout, online play is shut down, slow to earn cash
Need for Speed has taken many different directions, but the mid to late 2000's were the worst for the series. ProStreet is probably the worst NFS I have played, and I can't really recommend this to even hardcore fans. The game has good customization options, and varied event types, but after a couple dozen races you will be bored.
Races consist of earning a certain amount of points to "Dominate the Day". These events range from Drifts, Drags, Grip, Time Attack, and Sector Shootout. Sector Shootout is where you have a track divided into sections and you must get the fastest times in those to win. Grip races are straight up races, and the rest is history. Out of these events the Drags are the best because you need to heat up your tires before racing. You can only win by getting perfect shifts, but after you get NOS upgrades the drags become really easy. There are 1/4 mile and 1/2 mile drags, but I would have liked to see 3/4 and 1 mile drags as well. All the other races are pretty boring, and drifting in the game feels like dragging an 18 wheeler through dirt. No matter what car you use drifting never feels right, and is a huge pain to pull off.
The game was one of the first NFS games that used real-time damage which is supposed to affect the way the car drives but really doesn't. You can get light and heavy damage, but I never really noticed much of a hit in performance. If you damage your car you have to repair before the next race, but you can use cash or repair markers that you earn. My biggest issue with these "Race Days" is that if you quit in the middle you have to restart the whole thing. This drove me nuts because I couldn't go upgrade my car and come back.
Upgrading your cars is pretty fun because there are a lot of options for both performance and cosmetic. You can fine tune your car as well, but there is a quick upgrade option for impatient people. You can only have certain cars for certain event types, but you can only save customizations as blueprints. This allows you to have multiple looks and loadouts for your cars. I found that cash is given very slowly and parts are very expensive so you won't be upgrading very often which is a huge bummer.
Lastly, the game is just monotonous. After about a couple dozen races you will feel fed up with the same tired races over and over again. The physics feel too weighty, and most cars feel the same no matter how you upgrade them. The whole game is really unbalanced and poorly designed. The game doesn't even officially support the Game for Windows controller, and just show keyboard buttons instead. I just gave up about half way through because some races were always easy no matter who you did, and some extremely difficult no matter how good you were. The visuals are decent, but not anything to write home about. The announcer is just extremely annoying to listen to with his stoner one-liners and he just blabbers on about nonsense.
Overall, ProStreet wasn't very good when it came out and isn't 5 years later. There were, and still are, better racing games out there. I can't really recommend this game unless you like monotony and repetitive nonsense. ProStreet is half-broken, and highly unbalanced. As it stands, this is probably the worst NFS out there right now.