I've driven an SS Supercharged and an SS1 automatic. They drive nice, but I'm not a fan of the interior. It makes me feel really cramped. The supercharged model has some umph though, certainly a fun car.
No offense but the cobalt SS supercharged is crappy. the non boosted 2.4 SS from I believe it was 07 is better. The '08 turbocharged SS is pretty sweet. I have driven a few. It pushes 260hp and 260 torque. As for the N/A cobalt's they are not bad, but they sure as hell are not great. I prefer that over a newer Sentra. The shifter in a 5 speed cobalt is just... uh.. sloppy. The clutch does not have much feel. The coupe cobalt's do look pretty good though. There are also 5 speed cobalt's that get EPA 37 on the highway. The turbo cobalt is faster than most give credit to. It can not compare to a corvette though. I've driven 5 or 6.
Of course you can't compare it to a Corvette, or really any car that's not in it's class. In fact, I'll be the first one to say that the other cars in it's class come out on top, especially since 05 was the first year for the Cobalt. I just mean that it's really not a bad car. The supercharged model is quick enough for the price.