Does anybody have any experience with, or opinions on, the Osprey StraightJacket Compression Sack? I would like a waterproof compression sack for my sleeping bag, and was wondering if this would work well. Better or worse than a conventional compression dry sack?

http://www.ospreypacks.com/en/product/a ... ssion_sack

http://www.rei.com/product/882614/ospre ... ssion-sack