Guitar Hero 3: Legends of Rock is a great musical game. This franchise defined a genre and all of the games in it make for great party games. In my opinion, Guitar Hero 3 is the best Guitar Hero game. It is the one I have played a lot over the years, even having the newest titles. It plays like any of the other games. You can play in career mode or you can choose one of the songs and play it with your keyboard or USB guitar. You can play against your computer in a variety of modes or against other computer players. In the career mode, you play the songs until you get them right and then unlock new songs and guitars for your character. There are over 70 songs in total. I like that you can practice all of them or just parts to get better.
The Mac version of the game is published by Aspyr, who are doing a great job of releasing quality games for the Mac. This version runs very well on a 2010 Macbook Pro without integrated graphics. This is my first time playing the game on a Mac, and I can say that the experience was great. The game is just as fun on the Mac. I like that you can customize keyboard keys, for those without the USB guitars.
One note about pricing: Aspyr sends you to an Amazon page where you can buy the game new from $189.95. That is the price for the wired kit, which comes with an USB guitar. You can probably buy the game used somewhere else for a fraction of the price. I wouldn't pay $189.95 for a 2007 game.