Fastest Charge: PowerMax, Iota, PD, Parallax, Wfco
Given the nature of a battery (time/level of discharge and time to recover capabilities), I find it hard to understand how you determined this for all those converters in just 2 days. Just cannot be done in 2 days using only one battery to do the testing. Additionally, because each converter has different transition set points (Bulk, Absorbtion and Float), you have to know all the factors involved (level of discharge before timing recharge, surface charge removed before determing state-of-charge [SOC] after recharge, additional coach load requirements during recharge [affects amount of current available for charging], etc., etc., etc.)).
I would be very hesitant to make such a blanket statement based on such a limited 2 day test. The 3-stage converter/chargers from all of those manufactures are good 3 stage converter/chargers. I have already seen people saying things like the Powermax is a constant current charger (implying the others are not). In truth, that just says the people saying it really do not even know what a 3 stage charger is and what the term constant current relates to.
All 3-stage converter/chargers work on the principles described here: Charging Information For Lead Acid Batteries
The efficiency of a charging situation is directly dependent on the converter capability, battery bank size, and external coach loads.
A 45 amp 3-stage charger will not recover a pair of 6 volt T-105 225AH batteries discharged to 50% SOC as quickly as a single Group 27 95AH battery. AH (amp-hrs) is a measurement of energy and the more energy that has to be replinshed, the longer a charge cycle takes. Bigger battery, longer time.
There are limits as to how much amperage a battery (or battery bank) can accept during recharge. Increasing the amperage/voltage beyond that point will destroy the battery. Typical rule-of-thumb is 25% of amp-hour capacity otherwise gassing (boiling) and excessive battery heating occurs. A 225AH battery bank should not be recharged at greater than 56 amps in bulk mode. A 105 amp-hr battery bank (1 group 27 battery) should not be recharged at greater than 25 amps in bulk mode. As you can see, a 45 amp charger on a single group 27 12VDC deep cycle (or marine) battery has 20 spare amp for coach loads. The software in the charger can evaluate this and therfore limit charging amperage in bulk mode.
Sorry to have rambled on. The simple truth is there is more to the converter/charger or Inverter/charger vs battery bank type/size equation than what can be expresed in simple terms.