I used KFTG Front Range (Colorado Air and Space Port) last year. Easy to get to without dealing with the Bravo, tucked in Southeast of the international. I was only there one night, the FBO took great care of me in their hangar. They set me up with a car rental and made the whole experience painless.
Centennial in the South (KAPA) was a great lunch stop to watch the corporate jets coming in and out, but way too busy for my flying tastes.