Microsoft's premier racing franchise, Forza, has turned into one of the more under-respected but overall terrific racing titles on the market. Giving you the ability to make the game so hardcore that you cannot enjoy playing it to being so arcade-y that you cannot help enjoy playing it, it manages to somehow be the second best arcade racer on the market (behind Burnout) and, for my money, the best sim racer on the planet. I know, Gran Turismo is the racing game of the last few game generations, but the games, to me, seem to be little more than tech demos with a clunky single player experience.
Forza 3 takes the solid groundwork of the second game --- but just makes it better. There are more tracks, more cars, and more events. The series usage of the racing or breaking lines provides one a more solid insight into the mechanics of racing. It does take some time to realize just HOW to brake and Forza helps you as much as you want. Turn on full assists and you, basically, cannot lose. Turn them all off and you will learn how insanely difficult the car can be to control.
There are a number of different race types and a nice array of tracks. Naturally, you'll hate some of the tracks. You'll hate some of the race types. But you tend to change race types and tracks so frequently it's difficult to get burnt out on one type. You'll have to race speedways and the tiny streets of Italy. You'll race a ton of different cars. If you have any affection, at all, for driving in games then this game might be the perfect option for you. The game is also really good at scaling the sense of speed. Whether you're driving a hatchback or an open-wheel racer, the cars feel like they're going really fast at their top speed, even though the racer can nearly double the speed of the hatchback.
Some mechanics, though, seem pointless. When you raise a car's level, it makes the cost of upgrades lower. But when you raise the driver level, it just opens up new races --- except it doesn't seem anything changes outside of "Hey, you're now allowed to use these cars" and it seems like an artificial means of extending the game. The really fun cars to drive are the highest level cars. Far and away the best ones are those.
Forza 3 is more of the same of the excellent Forza mechanics. I don't ding it for being more of the same because great racing titles tend to not make massive changes. They just tweak what they have. And Forza has outstanding mechanics and great control combined with terrific track selection. It has more cars than you're ever likely to drive, so the actual number of cars seems a bit superfluous.