1. No visual customization options are available for your car
2. Multiplayer is very unorganized and mediocre
3. NO ONLINE POLICE CHASES
With that said, the single player mode is great. The races are challenging and invigorating with police trying to bust you in the race. The police chases become challenging in the upper levels with the spike strips, SUVs, and SWAT vehicles coming after you. It'd be nice to sort of have a story line to go along with single player and to have to earn your vehicles a little more.
The multiplayer is lacking, however. No online police chases. That was my biggest disappointment. To add onto that, all the games are based off of free roam and are unorganized and mainly involve just ramming other vehicles. You also cannot customize your car in multiplayer.