Originally Posted by bbbean

Don't put too much stock in the "aero bikes are stiff and ride rough" hype. My Propel rides great, is comfortable enough for me to ride 7-8000 miles a year with a substantial percentage of those miles being on rural highways in a wide variety of conditions. I test rode it side by side with a TCR and the primary subjective difference was a little weight (less than a half lb if I remember correctly). Both rode well enough that I made my decision based on the fact that I spend more time in the wind than I do climbing.

Compared to a Defy (my first Giant road bike), the aggressive geometry of the TCR and the Propel were a big adjustment, but in an A/B comparison, the differences are subtle.

You really should ride them side by side. There is no substitute for personal experience.