I've driven my G6 for 9 months now, and it's good and bad. It has some power, but the mileage isn't as good as the competition. The interior is poorly made, most of the buttons do not display their purposes anymore. Electrical issues for practically the whole time I've owned it.
It's built like a tank. It's my first car and it has done the job of keeping me safe, I'll tell you that. 3 car accidents, 1 of them my fault, and I've come out just fine. The cars body was damaged a bit, and the other cars always looked a lot worse. Like I said, built like a tank.
Better built quality. Everything breaks. GM has got to step it up. My next car will be an '08 Grand Prix, and that will be my deciding point for GM.