I must say that so far it has been a mostly pleasant experience. I have the red CTS and it does draw it share of raves from family and strangers. One draw back I noticed immediately was the width of the A pillars in conjunction with the side view mirrors makes for a sizable blind spot. Backing the car up is a bit of a guessing game since you can't see the rear deck. You can't count on the computer to give accurate gas mileage readings. On the instant readout the mileage jumps all over the place including into the 40 + mpg range. The average MPG was showing 30.2 at 65 MPH without the AC on. If it was really getting that kind of mileage I think it would have been show on the EPA estimate.
The overall impression of the cabin makes for a pleasant driving experience. The ambient lighting is a nice touch. You do have to have the dash lights set to bright to fully appreciate it. You can get used to the XM radio without the advertisements and useless banter.
Reduced blind spots. The 2 cup holders end up used for storage since they are in a storage area with a cover. A fold down rear seat. The cargo net is high and gets in the way when placing items in the trunk. A light in the engine compartment. Front cowl is 4 1/4" off ground. Should be fun in snow.