Santa brought me and my son two Incubator 20F UQs for Christmas, made by the fine people at Hammockgear. I must say the craftsmanship is excellent and the service is second to none!
Although we have only briefly used them (couple hours at night at 30F) we had no cold spots whatsoever. We can't wait for it to get a little cooler to really test them out. More info soon when we get a full night out with them.