I crawled into a MontBell spiral bag wearing my winter shirt, pants and socks at the store and was surprised to find it roomy enough to allow for my tossing and turning. The bag was not oversized. Sometimes I need to get up in a hurry at night and check on the llamas so I sleep in tight fitting undergarments, but never in a loose fitting jacket. During the coldest weather I drape my down jacket over the bag.

I was considering replacement of my Sierra Designs Rip Van Winkle which has elastic around the knees. I did not replace it and that is my only experience with the MontBell.