I ride a CX bike to school 13 miles each way with 30lb of books in a pannier and 9lbs of computer stuff in my messenger. It is pretty good though I never rode a dedicated racing bike more than a few feet so I can't tell you how much faster it will be. I did ride 26 miles on it yesterday with a bit of gear and it was fine. Took me about an 1.5-2hrs total. I run 34c tires on mine and will be trying it out with thinner 25-28c ones. As for the weight of the bike sure you can spend 3K on a 15lb racing bike but I spent $1.2K on a 19lb CX bike. For commuting you got to add things like a seat pack with stuff (2lb), a rack (3lb) bike locks (5lb) so your 15lb bike now weighs 25lb, negating the 5lb difference between road and CX with a $2K difference in price tag. I will say an unloaded race bike can FLY! and could I afford one I'd get one just for races.