The PowerMax is an excellent value. I just installed a Progressive Dynamics 60 amp converter:
https://www.bestconverter.com/PD-9260C-60-Amp-RV-ConverterCharger_p_171.html
I like it because it has a remote control pendant that you can use to select the voltage. The PowerMax requires using a small screwdriver, which would be fine if not needed very often.