I am an experienced backpacker with several 100 mi plus trips under my belt and one of the biggest challenges is always shelter. I purchased this for a weeklong trip to the Grand Canyon back country and was extremely satisfied with the outcome, including a night in the rain. I now have at least 20 nights in the bag.
Weight: While a little heavier than other bivys, the reliability of an Army Issue piece of equipment more than make up for the extra weight. All together I didn’t really feel that it added a noticeable increase in weight.
Packed Space: While lager than other bivys, this was still smaller than most compressible sleeping bags, and fit inside a med sized stuff sack from Walmart.
Interior Space: While this will be more cramped than a tent, There was more than wide enough for my Klymit Static V sleeping pad inside the bivy. This was great as I did not have to worry about rolling off my pad in the middle of the night. I also had my 5 degree bag inside. It was long enough to fit my 6’1″ body with room for a small camping pillow. There is no support for the cover so it will touch your face. Usually I can prop it up until I fall asleep, but all in all, its the same issue that you will have with any bivy. Regardless, the fabric was breathable and did not feel restricted in breathing, even when the product was touching my face.
Waterproof: GoreTex is great, I got rain on one night and with the cover over my face, I was completely dry.
Condensation: Temps on my trip dropped to below freezing and often that will create condensation. The GoreTex is very effective at allowing condensation out and with out loosing its waterproofing. It worked great.
Temp: Expect that this will add about 5-10 degrees of temp to your sleeping kit. With freezing temps, I was comfortable with a 5 degree bag and the bivy. In the summer, I have notices that it can become uncomfortable if it is warm and the cover is closed, but usually I just skip the sleeping bag and sleep with just the bivy. Which has worked great.
Durable: This has been up and down the Grand Canyon, In the mountains and several other locations. I am extremely pleased in how it has held up. Most sleep systems would be showing wear, but this still looks new (With the exception that its covered in trail dust.
New: Exactly as described, this was new and in the original Army plastic packing with the comply label slapped on it. Very happy that it was new as described as it touches your face all night when the cover is closed.
Overall: One of the best purchase I have made in a while for my outdoor adventures. It does weigh more but is worth the weight. In particular when you consider the overall cost.