Following DKRST's lead:
I installed another Aqueon heater in my 60g. Original was 200w, this one is 250w.
This does not prevent an over-run, but if one fails, the tank temperature will be maintained by the other. I've adjusted the 2nd heater for load balancing as close I can get it. The extra 'horsepower' could also come into play if the room temperature was to drop in winter (although perhaps a moot point in my all electric house!).
I like the Aqueon heaters as they are plastic covered aluminum (no glass) for durability and they have the red/green lights to indicate operation.