I got four TopFin heaters in a bunch of stuff I bought at a club auction a few years ago. They had all-metal-enclosed elements with external controller units, digital displays and remote temperature sensors. I love the idea of being able to turn the heater on/off or alter the temperature setting easily and while staying dry.
One works flawlessly, and has been in constant service for the several years since I got it.
One has never worked; neither control unit nor the element show any sign of life when plugged in.
One had a control unit that came on and responded to inputs, seemed to read the correct temperature, and attempted to turn the heater on and off...but no heat.
The last one had a heating element that came on when the thing was plugged in...and then never turned off as long as it had power.
Eventually I grafted the apparently-functioning controller onto the definitely over-achieving element and got a functioning unit with a big ugly "western union" in the cord going from controller to element.
So, with a bit of work, I ended up with two functioning devices out of four. No way I would ever spend a dime to buy one of these things new. "Reliably unreliable", lol...
Life may be like a box of chocolates...but that doesn't mean that half the chocolates should turn out to be deer pellets.