ignoring the trans since they were different, how else would you compare the c6 and c7? decent ones seem to be around 45k for c6 and 70k for the c7. thats so close to a used 5bw that i feel like i'd rather have the sedan form factor even if its not as loud and engaging as a z06 is going to be but did you like your c6?
I had a C5 Z06 and 'normal' C6 & C7 variants, all properly equipped with three pedals. The C6 was a big step up in interior materials. The base C6 had more horsepower than the C5 Z06, although IIRC less torque, weighed more and of course, suspension and brakes.
Aside from looks, which tends to be personal, the C6 was the last with hydraulic steering, as @evil said it had more buttons than screens, and the 7-speed in the C7 was, for me, garbage. Too many gears. I also had more problems getting in and out of the C7 than C6, mostly d/t dash design.
Although, personal experience only, the C6 has more issues with recognizing the fob, which can be very annoying.
I sold my second C6 to buy the aforementioned Supra largely because when it came time to decide what car to drive, the Corvette or the BW, the Corvette lost, and just sat there getting dusty.