I used the heated grip wraps from Aerostitch last winter, and they worked well for a NC winter. Actually, I just put them on this weekend again. Without the grip wraps, my fingers were uncomfortable riding in temp's in the 30's. With my regular gloves and the wraps, my hands and fingers were ok down into about the mid-20's. That was commuting to work, so I hardly ever got over about 45 mph. Only thing (and this was pretty minor) was some "hot spots" on the palms on longer rides. Moving my hands around, or switching the grip wraps on and off periodically cured that. They're simple to hook up too. I'd recommend them, but for longer, high-speed rides in cold weather, I'd probably spring for some heated gloves.
Will