i have a Felt Z carbon with ultegra 6700 bontrager x-lite wheel set and the bike weights in @ 17.2 so sluggish it ain't. it is quite responsive, stable, agile, comfortable and spins up great. i test rode a specialized and the biggest difference i felt was the ride quality, inmo the felt was superior I also have a trek madone, and 3 other steel road bikes . The flet rides better than my trek