I upgraded my wheelset from a pair of Mavic open sport to a pair of ROL SLR's. It was a $650 upgrade, I don't consider that to be a crazy amount of money. The very first thing I noticed right away was the rolling resistance. The hubs on the new wheelset were so much better than the old ones. I felt it as soon as I pushed off to start my ride. Overall a much soother ride and a small gain in average speed. Just my 2 cents