I used the Uber Bivy last weekend while camped in Tanaya Canyon just before the first big bowl. It was pretty windy and a bit chilly. I didn't have a ground cloth so I put my Z-Rest on the ground and the bivy on top of that. I had my inflatable 3/4 length pad inside the bivy. I had all my gear including boots inside the bivy and still had no shortage of space for stretching out. I used one pole which was placed in the slot that lofts the top. I did not use the slot that is on the edge of the rain flap. We did get a sprinkle after bedding down and I just reached out and pulled the rainflap over and zipped it up for the few minutes we had precip.
My only initial concern was that the Tyvek would be noisy and bother my hiking buddy. Not a problem as it did not crinkle at all once it was on the ground. One thing I did notice was that due to the slight stiffness of the Tyvek the bivy held its shape and did not get twisted up as I tossed and turned.
I was toasty all night and did not feel any of the wind. No condensation formed inside.
The packed weight was insignificant. The comfort of being able to move around inside a bivy without feeling any restrictions was great. This is one of my better purchases. My only remaining concern is that finding my sleep spot after a foray at night when snow camping will be problematical.
