Love them, lets me use a lighter weight glove at low temperatures to help with moisture control. I put them on around 28°f. Gloves can get sweaty but I don't worry about my hands freezing if I stop, cool and then restart. Also keeps me warm in wet conditions.

Side benefit I find is that if I'm about to crash it forces me to keep my hands on the bars for a proper fall, and prevents me from instinctively putting my hands out.