This game is just plain fun. The first part of the game is the Decepticon campaign to take over Cybertron. The second half is the Autobot quest to take it back. I didn't really expect to enjoy the game as much as I did, but after a few levels, I really got into it. For the uninitiated like me, I still found the plot to be surprisingly interesting. Believe the high reviews, this game is hours of Transformers shooting and smashing each other to bits with a fairly decent storyline. This game is often on sale and dirt cheap for the amount of entertainment you get. I would highly recommend buying this game, even if you're not already a huge fan of the Transformers universe.
One con: I had some problems with the controller support. However, I switched over to mouse and keyboard and ended up enjoying myself more.