[diffeomorphism]

> Which is better, the Dell Pro or the Dell Pro Max?

Neither. The precision lines are workstations addressed at a very different audience. So for the average customer the "better" ranking is non-pro, then pro and only in exceptional cases pro max. The actual differentiator is the blank, plus, premium afterwards.

Bonus questions: which models have ECC ram and quadro cards available? Which ones have the best displays? My guess would be pro max premium and non-pro premium, but that is far from obvious.