I have been playing Project Gotham Racing 2 (PGR2) for months now and have almost all of the cars unlocked. Almost. You have to play the game a lot and win the solo campaign on increasing difficulties to earn token and unlock cars. I'm unable to win all of the races on the most difficult settings which means I won't ever be using the two top cars in the game. But that's ok because I can still whip Action Replay lamers with my GT1.
Toca2 takes a approach to this by allowing you to just buy your way into all cars and tracks. For three quid (or a little less than 5 bucks) you can buy unlock codes. The game is good enough that I expect I will be playing it online enough to want to have all cars unlocked, so I bought the codes. I paid money for less than 50 characters of data.
A nice thing about this is that the solo campaign isn't won by paying for the unlock codes. It keeps that separate so you can play thru that campaign, which is, for the mast part, enjoyable. You go thru many races in various cars and tracks to become a racing superstar. The cut scenes are 'well produced' or so I'm told, but I think they are dumb and add nothing to the game play. Maybe I'm just more objective based when it comes to games and just want to know what that objective is without some story line matrix.
The races are not easy, and there's no difficulty setting (that I have found yet; more on that later) like there is in PGR2 (where you can do each races in one of five difficulty levels). But, you aren't expected to win each but instead get objectives like 'place in the top three' or come within two places of these other racers. I like that because it makes it possible for the race to be set up with many more cars and it places in back in the pack, so there's lots of overtaking (out braking your opponent is how to win) in the races. Overtaking is fun.
It's a racing sim instead of an arcade racer like PGR2. When you make a mistake, it costs you, especially if you break the wheel off of your Formula Ford (an open wheel race car). Power sliding is something to master just like it is in PGR2, but it's a more delicate art than the brute force, point grabbing slide-a-thon in Gotham. The different types of cars in the games this tough to do, because just as soon as you get used to the slow turning Formula Ford, you get into carts that turn on a dime. This variety is one of the major underlying features of the game and gives it at least as much depth as Gotham in the 'each car is different' category. I think Toca2 may do this better than PGR2.
Another variety factor in favor of Toca2 is the types of cars available to you. Open wheel racers, rally cars, classic street cars and modern super cars are all there. So, in one session you might be on the world renowned Nurburgring F1 circuit and the next may be a rainy, muddy Rallycross sprint over the moors of England (on and off road). PGR2 offers pavement in the day or night, or in the rain.
What Toca2 doesn't do better is the menu systems. The UI is nice and clean, and the loading screens are clever, but navigating around is confusing with odd names for some menu options (to get to Xbox Live games, you have to hit the 'Simulator Modes' menu). Also, one menu with 5 options might have three of them on the top of the screen, and two on the bottom, then when you select one of them, the next menu may be along the top of the screen in a horizontal row. There's a confusing quality to the menus that requires you to learn them.
Menu systems are not gameplay though. We buy and 'play' games, and Toca2 is certainly worth buying and playing. Since it's a budget title ($29.99) it makes the purchase of unlock codes easier to swallow and raises the 'value' of the game higher than if it was the typical $50. In an ocean of racing titles on the Xbox, you may overlook this one, but you shouldn't.