They work great and can be real life savers! I've got two. The better one is the PowerCat, because it's fan forced and has electronic ignition. I got it NIB at the swapmeet for $20! The other one sits on top of a propane bottle and is ignited with a match or lighter. I've used that one up in the mountains, once, and it really saved us! It got so cold up there and the heat was just enough to make us comfortable. One night, the heater ran out of propane and I woke up freezing! The cold woke me up and I just stuck another bottle on the heater and I was able to go back to sleep comfortable and happy. The PowerCat, I've only used in the garage. I've got a laptop, now, so I can "compute" wirelessly indoors, but before, I had to use my dad's computer, which is located in the garage. It can get really cold out there, and the PowerCat made it a little more bearable. I think I tried the other one in the garage, too, but without a fan, it didn't do much. It was great in a tent, though.