No auto off feature that I know of and it does stay warm. It's really easy to adjust the height - you simply screw/unscrew the legs. The chicks love it and it's the perfect size for my incubator. Since I can only incubate 22 eggs I'll likely only get 15-19 to hatch. The 2 times I used it the chicks used it not only to stay warm but as a shelter too. For instance when they were out roaming the brooder and I would stick my hand in to change water or feed they would run under the warmer to hide. It's basically instantaneous that they learn it's warm and shelter.
There are some threads on here where folks made similar stuff from hardware cloth and heating pads. Which would be a lot less expensive than the Ecoglow. But i prefer the simplicity. And the Ecoglow doesn't put off radiant heat. So it won't get so hot in the brooder like from a heat lamp. You'll want to adjust the height so that the chicks backs can feel the heating element. But not squish them ya know? I kept it just barely enough room for them to walk under it. They had to crouch to go in.