i just purchased the 09' 52" XO-1 over the poprad and bianchi axis. as for as class i feel they are all on the same level. it just came down to feel and preference. i felt more comfortable with the xo-1. the response of the xo-1 was smoother and not as stiff as poprad and bianchi. [fyi i am beginner, but i test ed each bike 4x with advance riders. they all agreed the xo-1 responded well. I get it this friday and i can't wait to get it on the road.