Matt Park wrote a review of Outdoor Research Water Bottle Parka on July 2, 2014
Familiarity: I've put it through the wringer
These things are awesome! they keep your water in a liquid state and they keep it close by. one of the biggest problems in mountaineering is not drinking enough. with these you can attach your bottle to the hip belt of your pack and then its always in reach, so you can get a quick drink on the trail without getting into your pack. I like to make hot tea on summit day and put it in a nalgene in a parka, and wrapped up in my down coat in my pack and its usually still pretty warm at the top!
also, if its not super cold you can leave your bottles in the parka in your tent and they do fine, you do not have to sleep with your water any more! that alone is worth it if you ask me haha.
I have been borrowing my buddies for years, and his have been through hell and back and are still going strong, i just got two of my own and expect years of awesome use out of them.