Zpacks Duplex versus MLD Cuben Grace + Serenity CF

I have been using a 9×8 simply light tarp with a BPWD 1.5 net-tent (w/ 8 inch sides). This is a fantastic setup and has performed very well in the cascades under all manner of rough weather. I’m looking to upgrade in the near future and thought to compare the uber-popular Zpacks duplex with basically a cuben MLD version similar to what I’ve been using. Zpacks doesnt really describe their dimensions in great detail and I am trying to calculate approximate ground coverage. In the cascades it is wet…..a lot, and I like to keep my soaked gear (shoes backpack etc) out of my bathtub dry space so vestibule or tarp overcoverage counts as a valuable commodity. Duplex people….have you actually had two people in your Duplex?….in the rain… and did the vestibules work adequately? Please discuss the pros and cons of each of these systems.

Zpacks Duplex 0.51CF $600 21oz 

28 sqft interior plus 7.2 sqft * 2 = 14 sqft vestibule coverage

MLD grace duo + Serenity Bug Shelter duo 0.71CF 600$ 22oz

28 sqft interior ~16 sqft *2 = 32 sqft tarp coverage (pitched to ground)

Thanks!

Drew