Great game, wished they would have spent a little bit more time making a more complete game.
The major advantage Crackdown has over other games like it (GTA) is that you are actually the good guy.
Overall the game is worth buying because you can play online with a friend through the whole of it and still have a super fun time doing it. You can help each other out by swapping guns and then killing bosses. It also has a good RPG element to it where you level up certain skills. You can waste a good week on it playing with a friend a few hours each night. It's a nice casual game you can play with a friend when you are talking or deciding what you should play.