I store my Thermarest Basecamp XL and Tennier MSS bag unrolled so that I don't compact the fill any more than necessary. I just hope that in an emergency I have 10 minutes to roll both of them up and attach them to my BOB.

In both cases, the manufacturer suggests that the items should be stored in an uncompressed state. It's probably a good idea for the equipment's longevity, but I don't know if it will prove to be a problem in an emergency.