A wonderful blend of casual multiplayer and intense single-player.
There are drawbacks, however. In single player, if you happen to buy an upgrade, guess what--all the computer-controlled vehicles in any race you enter the the SAME EXACT UPGRADES. This completely undermines the the option to upgrade. Also, if you enter a multiplayer game in which the host has selected a custom track that you just so happen to not have, someone who knows the url has to type it in for you, then you need to switch to a different menu within the game and type in the url again!
On the other hand, it is possible to play this game through a dial-up connection. The players may experience a tiny bit of lag, but it's bearable. Also, there is an array of teams to choose from--including the Low Riders of America, wrp, and many others.
I would recommend picking up this game if you happen to see it laying on a 10- or 20-dollar shelf if you're looking for a couple of cheap thrills.