50 gph is easy to achieve with minimal effort in my ffe, but the fact that subzero and bizzy bee’s systems are proven and have a 3rd party review puts them at a bit of an advantage. I agree you are paying a premium for the systems that are 150k (even mine is 150k) but these machines, including mine can pump out 20k+ of revenue per hour. The amount of money you will lose for downtime outweighs the initial cost. Whoever you buy from, I would consider buying multiple pumps and having the ability to run your cooling system off water.
Didn’t really wanna hijack the thread but here is mine 50+ GPH FFE for sale 150k - #15 by Apothecary36