>>As long as I'm clothed, I find them not bad. Any exposed skin sticks to the material and adds to the noise and discomfort.<<

To each their own, I guess. I "slept" one night on the hood of a Ford, on a barrier island after an amazing storm, in the middle of a sea of knee-deep mud. That was worse, but...

I spent the better part of one night under a space blanket (haven't tried the bags) The thing made noise when I BREATHED, I was either too hot or too cold or parts of me were both, and humidity built up rapidly under any part that was covered, and it got sweaty, while any uncovered parts were freezing off, keeping me constantly moving. And it tore if you looked at it funny.

To be fair, I was having leg cramps at the time as well, which was unrelated (apparently salt depletion, I learned later), but I'd get these amazingly acute "charley horse" pains, and have to get up and dance around in the cold awhile to shake them off, by which time I was shivering uncontollably again. I think I slept a little that night, but I remember every minute of the dawning that morning, and I didn't come out of it with any affection for the space blanket at all.

Y'know, after your response, it occurred to me that I've never actually tried the Thermo-Lite bag, even briefly... just looked at it and put it away. Probably should have kept my mouth shut about it.

I have used the Thermo-Lite blanket, and it did much better. I took the blanket instead of the bag because I was traveling in an area where I thought rigging it as a sun shelter might become important, say, if the vehicle broke down... should be much cooler than inside it. It didn't come to that, of course, but it's something the blanket would do much better than the bag in the desert.