I've driven it for over 3 years now from when it still had the plastic on the seats. I bought the 06 model because I did not like the 04 models (too plain -- no hood scoops, sometimes no spoilers, etc). Mine has a higher 'sport' rear spoiler, but personally I believe if you're going to drive a muscle car, let the car look the part a little bit, or else just get a sedan. The cabin isn't bad, for an American muscle car it's fairly classy actually (at least compared to the way the older GM sports cars used to be -- Camaros, TA's, etc, basically all plasticky and cheap-looking really).
Overall, on a daily basis, it feels solid, but a bit heavy. Handling does not exactly feel razor-sharp, in my opinion, but it's not bad either. These cars ride generally on the harder side and rather lose their composure, in my opinion, over anything but the smoother roads. So this constant bumping around over any roads with any kinds of holes and pits can be quite annoying at times. Braking is strong (and the brakes with the red GTO calipers look cool too).
Ice-cold A/C in the summers, and good warm heat in the winters -- although the car is not truly drivable in snowy or icy conditions due to its RWD, its torque, and the Z-rated tires it sits on. You really need to have access to a second car if you live anywhere there's a real winter.
You'll get, unless you are always on the expressways, only around 13 - 14 miles per gallon, even without your foot in it all the time. That can get a bit expensive when gas prices spike. You'll gas it up about once every week, if it's your daily urban or suburban driver, and a tank will cost you around 35 dollars in this car (as of summer '09). But when it had spiked last year it was much more, and that's about once a week bear in mind...
Insurance = a bit on the high side, due to the HP rating, etc (and it's much worse if the primary driver is young, of course).
Overall it's very reliable and livable as a day-to-day driver. The 400 hp in this car feels more linear to me, rather than explosive, although there are some serious power points. Putting it all the way to the floor from a light, especially with the traction control off, will have you burning rubber and even fishtailing. I have even fishtailed it (with T/C off) and ripped the tires pretty well while already going over 30mph. So, I guess if you really get aggressive with it, it can be a little 'explosive' after all. But it feels more like a Clark Kent/ Superman type of thing (easy to drive with windows up, slow music and A/C on, not a ton of road noise or rattles, etc, like my older Camaros always used to have, but also capable of throwing down at the drop of a hat). All around, thumbs up, I'm a satisfied owner and my 'goat' and I are tight. The only reason I wouldn't personally buy another Pontiac is because they just got completely discontinued due to GM's current financial 'situation', etc.