That having been said, I purchased this unit and had it in my motorhome:
It's a PM3 55amp unit. I was happy enough with it that I purchased a 25amp 24V version for another project so that tells you how I felt about it after having done a fair amount of research. I was pleased with it in my motorhome and it was a nice upgrade though I've never had the Progressive Dynamics as a comparison.
Oh and I'm fairly certain they all have a similar charging profile, as a general rule there is never harm in having more amps than you need other than if it were say a breaker designed to protect the wiring. I wouldn't get too much more than you need either but this unit is just meant to power your DC system and charge your batteries when plugged in so having more amps likely won't harm or help. For example, if you were going to do an upgrade later so you chose a larger unit now there wouldn't be any harm in that.
I have a power supply in my computer that's designed for twice the load, I normally oversize to run things at half their rated ability. Even my grid tie inverters are 1,000 watt but only have 600 watts of solar
to them. Again, confirm this information on your own but that's why I tend to do things.