I am an avid all year round BWCA camper and I purchase this bivy for my 2008 January 3-day, 7-mile ski and 1/4 mile hike up 300 feet to our favorite spot.
I am very satisfied with this bivy with only one minor issue; it's hard to get into quickly when you have -5 degree weather. I experienced very little condensation and it was very easy to resolve what condensation I had by unzipping a little to vent. I customized a thermo-lite pad to slip inside the bivy and used a -0 degree sleeping bag and slept in my long under ware. I was 100% dry and warm in the weather I experience, (Snow, rain, and very cold (low as -15 degrees) damp weather). I found that there is more than enough room to sleep in all positions and I am a 5' 7, 200 pounds. This also packs very small and is light. Overall I am very pleased and can't wait to use it through out the other seasons!
Here is a link to my bivy in use on the trip http://www.frontiernet.net/~jt9786/BC_gear/ORBIVY.html

I bought this bivy to protect my down bag in a snow cave. I have not used for that purpose yet but I did throw the bivy with my synthetic back out in the rain for a day to test it out a bit. In an hour of medium rain the top had soaked through and started wetting the bag. There was also a large amount of condensation granted the bivy was full zipped up. I would recommend this for use under a full size tarp to protect your bag from splash and water on the ground but would not trust to stand alone in any kind of storm.

The bivy was great. The bivy is perfect for what I want it for. It is very light weight. The bug net is great, because at night there are tons of bugs and zipping that up allows me to stay cool without bugs. I would recommend it because of the relatively cheap price. The only bad thing about it that there is a little condensation, which you can expect from almost any bivy.

I have used this in freezing temps, light rain, snow, and even blistering hot weather. This bivy performs in all of it! The condensation stays on the outside of the bag and thanks to the pertex liner it is pretty waterproof and extremely packable and lightweight. I highly suggest this bivy and using the loops to guyout the top to stay out of your face or wear a cap.

I have tried several other bivys, and had problems with too snug fit, xs condensation, and seam leakage. The OR has worked well on a 5 day ridge running trip in Glacier Nat Park end of September. It improved my sleeping bag warmth by 10-15 degrees F, and kept me dry in a light rain. Plenty of room inside (I'm 6'1", 175 lbs), and the loops on the front are great to keep the netting off my face when suspended from hiking poles or branches. Easy to enter and exit. Folds up small for packing, very light for it's features, very happy with my purchase. Very useful for light, fast, high mountaineering.

It is so light and easy to pack that you forget its there! My first bivy and it has kept me warm and dry so far. There is a little condensation but its a bivy.

This bivy is just too big and heavy to be of any practical use.