Any heater can fail, and if it fails in the 'on' position you generally have more problems. I read several fish-related boards with regularity, and I've not noticed any rash of complaints about Ebo Jagers. (In fact, when people mention they fail, it's generally received with some surprise.) Tronics have a good reputation, but I just had one (about 18 months old) fail in the 'on' position.
There are two ways to protect yourself from heater failure (that I can think of, anyway). First, your can buy brands that have a good track record. Ebos and Tronics certainly fall into that category; I'd stay away from anything with the name PennPlax or Accura on it. Second, you can make sure that no one single heater in your tank is large enough to cook your fish should it fail. Distribute your heating over multiple heaters, each too small by itself to raise your tank temperature beyond safe limits. For example, in our cold house, I use about 4-5 watts per gallon to heat my tanks. On a 75 gallon tank, I need 300- 375 watts of heater to maintain a stable temp. I use two 150w or three 100w heaters; by itself, none of the smaller heaters could fry my fish (at least during winter months).
Good heaters are not much more expensive than crummer heaters. It doesn't make sense to me to scrimp on them.
HTH,
Jim
