Welcome to the XBox side of things. Having played GT1 through 6 and FM3 through 7, I feel like both games have strengths and both games have weaknesses, but they're both fun and you can't lose no matter which one you go for.
Here are three tips for getting a little more out of Forza Motorsport:
1. Do at least one League race a week. You don't even need to win. Just compete, and you will be awarded a free car or driver suit. Yes, it's online racing, but you can choose ghost racing so no one can ram you. Every four weeks there's an additional free car or suit. So that's five gifts every four weeks as long as you complete one race a week.
2. Do the Forzathons. There are monthly and weekly challenges that have big cash, car and driver gear rewards. There's a
dedicated thread for Forzathons that
@Htsaeteurn is keeping up to date. Subscribe to that thread and you won't miss out.
3. Check the specialty dealer. Four different cars are offered at discounted prices every week. Every once in a while, they're even free, usually around Christmas.
And lastly, have fun.