I know there are a bunch of threads on this pack, but I recently got mine and figured I would throw my 2 cents into the pot. I had been drooling over this pack for a while, but when taped seams and other nice improvements like the newer side straps and such, I just had to have one. That, and I had already read a lot of good things about it on here and on blogs.
My first impressions are that I am very, very impressed. Can't wait to try it in the field soon. I got Joe to do a mod that I thought would work out well–two smaller center pockets rather than one–and I think it turned out great. Seems like it will be easier to organize and find my gear on the outside of my pack.
You can read more about my initial review, along with a long term review of my Zero, here:
http://cesarandthewoods.blogspot.se/2013/09/zpacks-backpacks-double-review-arc.html
