I drove a C6 coupe with the Z51 package and the A6 with paddle shifter. The paddle shifter doesn't look that great but works well. The car definately felt faster than the GTO, but that's the difference 550lbs will make. GM blew it by not putting that tranny in the GTO. There are 3 modes to it Auto, Sport Auto and Sport manual. I was told if you put it into manual it will not shift. The only difference between a manual and this is no clutch and you just about can't blow a shift. No 5-2 downshifts if you will over rev. I tried the paddle shift and it was well designed. It clicked shifts right now. It was very intuitive in its usage. The sport Auto mode is cool too. When you go into that it is set up for track driving and downshifts when you lift off the gas in certain circumstances and it also downshifts as you brake to a light. It's shifts were real high in the rev range. It was about 4000 from 1st to second, and about 3500 2nd to 3rd with just moderate driving. Made the car feel like it wanted to run. The shifts were crisp enough to chirp the tires at 4grand on the 1-2 shift. Switching it to regular auto made it feel like a Buick.
The C6 is worlds ahead of my C5. The Z-51 felt like it handled as good as my Z06 and the ride was almost as good as the GTO. Lots of nice features throughout the whole car too.
The final question is, is it 22,000 better than the GTO when new. I'd say yes. Now I need to give them 31,000 to get it. I'm thinking no. I definately a fan of that 6 spd auto though, and having driven it could never buy a 4spd auto LS2 powered car.