I traded my 2001 GTS three weeks ago for a SRTC.
I am very happy with the move. I briefly thought about a z06 but decided on the Coupe. A split second better in 0-60 was not enough to offset some things I really liked better about the Viper. Specifically, better interior(people probably think I'm crazy, but I like the Viper interior better than the C6), Coupe styling hands down, side exhaust is very cool and it came in GTS Blue!
I am not a racer so my appreciation for the coupe is the styling, build quality, and driving experience.
1)I think the styling is great. Not as wild or balanced as the GTS, but more modern and still gets plenty of looks.
2)Build quality - I think both cars build quality were excellent. The 06 interior is years ahead of the GTS(I guess it should be since it was designed years later!). I find it more comfortable and the stereo is much better.
3)Driving Experience - Definitely more refined and more enjoyable on longer drives.
Regrets - None, I always loved the Bright Blue GTS color or Nassau Blue on my corvettes so when the Coupe was available in GTS Blue that helped me make my mind up.
Good luck.