[Desmodus]

I use my JT thermals pretty much religiously. I have never once fogged up while wearing them, and I can pretty much fog up anything since I'm the latino heat. I tried ESS NVG's with the foam removed and those fogged up more than the city of London.
My only gripe is that they are rather big/bulky, so it can make fumbling with pouches on your rig a little difficult.