The main problem with the WFCO is improper installation chosen by almost all RV manufacturers—mounted far from the batteries and connected with a long, 0/2thin wire. They
know it will never go into boost because they protect the wire coming from the converter to the batteries with a 30amp breaker at the battery end. I discovered this when I moved my converter next to the batteries.
linkThe converter needs three things to operate in boost mode:
1. Mounted close to the batteries (mine was 30 wire ft away)
2. Connected to batteries by short fat wire (mine was #8)
3. Converter size matched to battery bank size. (mine was 1 gp 27)
A converter too large for the battery bank will trip the 14.4v setpoint quickly and drop out of boost with the batteries remaining at a much lower SOC.
The most annoying problem is the poor PF which makes it hard/impossible to power in boost with a 1k generator.
I can't speak to the longevity as I rarely/never run mine anymore with the solar doing all the work.