"Rusty...I didn't realize the Zen pack was yours as well".
Even had a hand in the name.:)
"Looks like the perfect summer or overnighter (I'm not quite at that UL stage yet)."
So far, I've only used it on overnighters. I keep whittling at and fiddling with my gear though so am thinking it'll work fine on 4-day summer trips.
"What are your feelings on the Cuben's longevity?"
I don't have enough experience with cuben to opine much. So far, from what I have seen with my cuben shelter and have read here, I have no concerns. I consider myself very careful with my gear though.
"My pack actually drew inspiration from the Mahan, Gowler, Fogarty, and Exposure/Zen packs."
Is your pack on Zimmer's site?
"Has the shockcord compression on the Exposure or the Zen proved a better design??"
For real compression, where I'm actually trying to make the pack trimmer, I prefer straps over shock cord. For simply taking up slack in the pack, the shock cord would be dandy, I think....but, considering that I put my sleeping bag in the pack sans stuff sack, and the fact the pack is small, I don't use the shock cords for that. I have no slack in this pack. I do however like how easy it is to hold stuff down on the exterior of the pack with the shock cords compared to straps. Hope that answers your question.