I've also used a Keis waistcoat for 21/2 years now. The waistcoat is very effective and for the price (its still about the same as I paid and often discounted), I'd say go for it. The problem with Keis heated gear, (I also had a pair of the in-soles), in my experience is the wiring is not very durable. I've just had to repair the cable to the waistcoat controller again after it split. Keis also use a smaller size of coax plugs to other heated clothing manufacturers which can be a problem if you want to link it up to say a Gerbings controller.
