The eheim ones are not that much. If you buy the really cheap ones they have a greater chance to fail. I boiled my fish once in a 30 gallon due to a 3 month old heater failing. Most decent heaters are only a few bucks more than the cheaper ones. But that is my experience in trying to get cheap ones on my tanks.
I use all Eheim ones and on my Discus tanks I use the Finnex controllers to be double sure and never had an issue with my heaters since.
There is no such thing as a cheap heater. You may pay less for an inferior quality item. However it will cost you more if it fails and you're not around. It only took me one time to learn that lesson back in 1981 with a "cheap" air pump. Never again.
I've been using a ViaAqua heater for more than 1 year. Still working great. Doesn't mean it won't quit tomorrow but same can be true of other heaters. I like that is has easy to read temps and it's easy to adjust withOUT using 2 hands.
I also have an Eheim Jager heater also been in use a year but it's hard to adjust. Mine takes 2 hands .. one to hold the heater & the other to turn the dial. It's really hard to turn for some reason. And I've accidentally turned the calibration ring instead of the temp ring requiring me to recalibrate it. But then again it's nice that the Jager CAN be calibrated .. a definite plus.