I get the impression that many of the WFCO haters are dry campers who need to get every last amp-hour out of their batteries, then have them recharged as quickly as possible without damage.
I have found my seven year old WFCO to do a fine job of keeping my lights and appliances running and the battery charged while on shore power, which is all the time.
The point is, you can't reasonably say that a Hyundai sucks just because it isn't a Mercedes.