Matt G.wrote a review of Big Agnes Three Wire Bivy on July 11, 2017
Familiarity: I've put it through the wringer
The E-Vent material works great at preventing moisture build up, although there have been a few very cold nights where small icicles have formed inside from the condensation. I solved this by leaving the zipper open an inch or 2 unless there was rain or snow. It retains heat moderately well, and is very, very waterproof. In warmer temperatures with the zippers completely closed I have noticed next to no condensation.
I have owned this bivy for nearly a year and have used it mostly in Oregon and Alaska.
Very easy to set up, screen mesh and side zipper are nice. Lots of space for a bivy. Can stash your pack if you are on the shorter side. I am 6' and can't really do it, but still plenty of room to stretch out. Fits extra long sleeping bag and thermarest no problem.
Wish it packed down just a bit smaller, otherwise love it.