I have an All Glass Aquarium (AGA) heater in my main tank and 10 gallon. The heater in my main tank is controlled by the AquaController Jr, so no worries about it possibly "sticking" in the ON position. I've got a 300W heater in my 55 gallon, and on the rare occasion that it turns on, it restores the proper temp in no time. The 50W heater in my 10 gallon seems to struggle to keep the temperature up.
So far the stealth is the one to have, but in 20 years I have never seen one that you can set at a temp. and have the tank run at that temp. Most companys guarantee there heaters within .5 degrees. I have never seen one do that!! There is noway , because of lights and pumps and so on that you can set a heater and walk away. You always have to mess with them.
I dont know my visatherm I set it buried it under my rock in a higher flow area and my temp stays dead on all the time right where I set it
now true if I had the money I would have a controler that was set just above what I have my stealth set at so that IF it ever did fail in the on position it would have a failsafe