I love my bar mitts, too, Thorn, and purchased a couple extra sets (one to fit my Orbit, which has campy chorus, and a second--in medium--for my Seven). Today was probably the coldest ride thus far of the season (mid-30s) and my hands stayed super warm, despite a brisk wind (actually, my hands were sweating because I wore heavier gloves). My Isis is outfitted with the small bar mitts--that bike has a much smaller handlebar than the Seven.

Like anything else, you get used to riding with them. At first, it feels a bit freaky but it's more than worth the acclimation factor for the warmth factor.