Mug Press Heating Elements Quality - Bad Vs Good

[RobertB1]

I’m just thinking... a lot of different mug press companies use the same controler (300W: preheating function: temp and time setup...)
You can get controler box for 20$ and the whole press for 40$, but there in my opinion is something else - heat element quality.

What makes them better or worse? Why some last 200 mugs, some 1000 mugs, some don’t heat on the left side, some on the right...

So where is the trick? What is different?