55a for under $200 is by far the best bang for the reliable power supply buck that i have found. sure it will eat up 1600w @ full load most people have a 3k generator @ minimum anyways. Server supply's are great, they just seem to be temperamental at times.

Non PFC supplies do tend to be less expensive, and in many (most?) RC uses are a very viable option. I just question the resulting tradeoff of a bigger generator, increased current driven power losses, and possibly increased wiring sizes, at higher power levels. I’d rather use a smaller generator and/or have more power available for a multitude of other possible uses.

The links have prices of $235 and $278 for the 750W supply? Cheaper somewhere else?
Here's a 750W job with PFC for around 200, in a choice of voltages:

750W supply with PFC

EDIT: Ah, yes, they are available cheaper, $160 for example:

Iota 55 at ProgressiveRC

I doubt we will use all at full load. Maybe 2 or 3 lipos being charged at one time maybe a Rx or Tx charging too. Do you think the iota 55a would do?

Depends on the voltages of the batteries being charged. But to give you an idea, that’s enough power to charge three 4S lipos at about 9 amps each at a time. Assuming the ~13.4 amps needed for the supply are available, and sufficient wiring.

3 lipos times max voltage times charge amps / charger efficiency times power supply headroom:

3 x 16.8V x 9A / ~80% x 130% = about 737 watts.

The voltage would slightly limit any single DUO, to about 330W, instead of the full 360W capability with higher supply voltages.

One thing to remember is these iotas are more of a battery charger/replacement where the others are power supplies designed for computers.

If I was doing this in a permanent mount like a trailer is wire a deep cycle 12v battery inline with it. A few things it will do is keep the chargers on if the gen runs out of fuel or is not hooked up, even out any draw spikes over 55a, clean the power up. If you have anything sensitive it would also give you something to regen discharge into.