This is the newer version of a bivy of mine that I have used extensively over the years, bivying in it for 21 days, well -1 night when I crawled into the tent with my friends. Anyways amazing, breathable, my sleeping back is never soaking and I have slept many a comfortable night in the snow. perfect for light and fast ski traverses. Packs small.

I've used this bivy in two of the most extreme conditions I could find on a college budget. My brother and I snowshoed into Snowy Range in February where we encountered 50 mph winds on top of -10 degree temps. I also used it throughout Wyoming this summer encountering multiple rainstorms, one of which got the best of the bivy.

My first praise is that the Marmot Alpinist Bivy is very roomy. I'm 6' tall about 180 lbs and had plenty of room for camera equipment, boots and and my clothes. It has enough room that I'm working on fabricating a lightweight skeleton to add headroom and keep rain from pooling on top of my face once I'm tucked in for the night. I wouldn't hesitate to nestle up with my pack in the Alpinist if the conditions demanded it.

The bivy was also very durable and light. I consider myself pretty careful when it comes to gear handling, but I wasn't afraid to used it atop my pad, which rested on a bed of pine needles and branches on my snow hike.

One of my concerns, though, was with the size of the bivy. Unless you are camping on a perfectly flat surface or in a trench like I dug in the snow, the bivy will allow plenty of room to roll and slide. I found the zipper hard to find some mornings as it was often underneath me.

Another thing that caused some concern was the breathability. There are plenty of reviews out there that say this is a strength. However, I found the bivy got quite stuffy in about 15 minutes - enough so that it made me worry about suffocation. It's definitely possible with this bivy - hence the multiple warnings on the tags.

I would have liked screen or mesh integrated into the zipper system or underneath the hefty rain flap. The 50 mph winds I endured up in the Snowies kept this bivy well ventilated, but before they picked up there was considerable condensation inside.

While camping at Sinks Canyon in Wyo., the bivy held up well against a downpour. Unfortunately, the size of the bivy and the zipper combined malfunctions to create a sink of it's own, directing most of the rain into my bivy.

Looking back, keeping the zipper shut further would have been beneficial. While the three zipper heads allow you to have two smaller holes instead of one big one, the condensation that built up inside the bivy was enough to lightly hurt my down bag anyways.

I'm hoping that whatever skeleton I'm able to come up with will keep a good amount of the condensation away from my bag and allow the rain flap to be used to it's full potential.

With integrated mesh, this would be a five star bivy hands down. With some fine tuning, it will be the only shelter I need.

this thing is awesome! turns a 15 degree bag into a 0 degree! it survived the grand targee bluegrass festival, no matter how drunk you are you cant hurt this thing.

While this bivy is light and packs nicely, the zipper placement is very strange. It starts from the middle directly above your head and goes down to your shoulder.