Replacing the OEM WFCO converter with a Progressive Dynamics was one of the first mods I made to my ACE 30.1. WFCO converters are not the best for batteries. The OEM Harris batteries the coach came with lasted less than a year - I think a combination of cheap batteries, poor converter and maybe sitting in Thor's inventory too long. Harris generally doesn't honor warranties and points to the converter as the cause of failure. I now have a "good" set of Interstate 6V batteries and a good converter. Just added a Trimetric battery monitor to help keep it that way.
The Progressive Dynamics unit was a direct slide in replacement for the WFCO converter. Check what model you have and look up the correct replacement on the Progressive Dynamics web site. They list direct replacements for a couple of converter manufacturers and sizes. Change out took about 45 minutes, about 15 minutes of which was consumed by trying to slide the new unit in the wrong way (coils on the original with on the back side, but the PD unit has them on the front side). Once I figured that out it it was only a few minutes. Just two sets of wires - AC in and DC out which connect using the original cables.
I also found that the DC distribution board shipped with the PD unit wouldn't work with the way my coach is wired. The original board had 40 amp main fuses while the PD board only had 30 amp main fuses. Talked with PD and they said just keep the original board. Only loss was the status LED and mode button. I bought their dongle. which does the same thing. They said that they were looking at changing to a 40 distribution board, but hadn't got there yet.