Got one. Agree with above - the shifting is -not- instantaneous, up or down in the 2006 paddle shift cars. GM reprogrammed the speed of the shift for 2008 but I don't know if the 2008 programming works on the '06 - I would hope so.
The paddle shift cars give you an antomatic car with 'manual' shift capability. If you like the idea of letting the car do all the shifting most of the time yet get the benefits of 6 gears and 'manual, sequential' shift mode, it's hard to beat.
The paddles take a little practice to get used to but it doesn't take long. When you don't want to shift everytime, leave it in "D" or "S" and don't touch the paddles and it takes care of shifting for you. My wife drives our '06 daily and rarely touches the paddles. When I'm driving it, I play with the paddle mode. It also works very well on autocross and hot laps on road courses.