IME the most reliable heater is a Ranco controller with a titanium heating element plugged into it.
Ebo-Jaeger heaters used to be the gold standard, but ever since they were purchased by Eheim a few years ago I saw their quality decline, so I am not sure what is best now. I have a 250 watt Stealth in my plant tank, and it works just fine and has been for a couple years.