You will note the "Max " in the Go Power converter line nowadays (they used to re-brand Iotas) Now they are PowerMax. Same same except price! IMO Go Power has high prices. Randy and PowerMax has good prices by comparison.
You need high amps to fast charge four batts. The PowerMax 100 would be ideal for the price. It has one disadvantage, in that it drops to 13.7v for Absorption voltage vs 14.2v for Iota. But this has no meaning when on shore power or if you have solar.
On solar, and for some reason like cloudy days, you get down to 50% SOC, then you want a quick shot of gen charging in the morning using your fast charger (the PowerMax 100 amper) and it will get you back to 75% SOC in quick time (an hour or less) then drop to 13.7v and go to slow time at that voltage. BUT, now you are back to 75% SOC and you have all the rest of the day on solar to get caught up so you shut down the gen and go solar.
So IMO (I have a PowerMax 100amper and solar and dry camp with four 6s) you would get no advantage for the higher cost of an Iota 90, plus, and this is very important as mena said, the PowerMax has power factor correction so it can run on an AC 15a circuit.
