It arrived rolled up in a box and I couldn't conceive as to how it would fill out to be the large, heavy object it is, which took a few hours to fully swell to its correct volume. 
After several nights of sleep on it, I can vouch for its comfort level. Slightly firmer than I was used to previously, but that's probably no bad thing, and I got accustomed to it quickly. I also bought the protector, so as to keep it as pristine as possible. I have been enjoying climbing into bed, to swim in luxury, and lazy lie-ins with cups of tea (if my cats allow me the space).