My fav used to be Ebo, but after hearing nighmare stories, I've switched to non-glass titanium heaters. So far, only a little more than a year of use doesn't tell much of their reliability.
I'll be the voice of dissent. Bought one ebo jager a few years ago, put it in tank, ran it a week, then poof, nuclear tank (95+). Ebo fused its contacts. Ebo into trash, I went back to Tronics. I've run dozens of Tronics over the years and never had a single one do anything other than keep my temp to within 0.3 degrees of what I set it.
i saw somebody suggest a visa-therm i've had 2 of these blow up in tanks and i would not suggest these heters. they dident stick just actually blew up and shattered in the tank luckely for me they blew the heating element out of the tank when it happened or i would have lost some fish.
I've used a variety of heaters over the years and have had problems () with many of them, fortunately no catatrosphes yet.
Nonetheless, I now use a group of smaller wattage heaters connected to a controller. My logic is that if one does stick, it alone doesn't have enough "juice" to really fry the tan. Secondly the controller will override the problem of any sticking elements of a heater.
IMO, get a temp controller and you don't have to worry about the heater "sticking." The controller and heater would have to "stick" for a problem to occur.