I have much the same question.
I'm looking to upgrade and am trying to decide between a Waterbox Marine X 110.4 ($2,200) and an IM Nuvo EXT 100 Complete Reef System ($2,770 on sale). The IM is larger, and it has the "Bean Animal" external overflow plumbing. The Waterbox looks better (pure aesthetics, not talking functionality. This is a matter of taste, obviously), and has an RO reservoir in the sump. The IM doesn't have an RO reservoir, and by the looks of it, there's not even room for one inside the cabinet. I'd have to place it outside.
The bigger question is, which is best for a sump newbie? Which of the sumps is easiest to access, and easiest to dial in for someone who's never had a sump-based tank before?
And, is there a difference in reputation/quality? I've only read good things about both. Is that accurate? I did notice that Waterbox gives you 2 years of warranty included, while IM only gives you 1 year. You can pay to extend it to 3 years, though.
Appreciate any insights, thanks!