I've got both X0-1 (2006) and F1X (2007) ... The XO was really basic but a good work horse.. but I will be using my F1X as my race rig this year. I havent seen the new XO lately but in referring to mine it makes a DECENT entry level bike but doesnt have the nice little touches such as a flat top tube near the seat stay for carrying like the F1X does... the Mavic rims are a bit on the heavy side but make good trainers on the F1X where as the Bontragers on XO are much lighter... hmmm.. thats pretty much it other than the previously stated dérailleurs differences...