I have the medium firm mattress. Everything is very well thought out with this thing. The materials are great and make cleaning and maintenance easy. The velcro that secures this to the bed is a really nice touch. I have the full FVC bed as well and this mattress is actually a little thicker and more cushioned than that—I slightly prefer it.
When it's just me and a bunch of gear, the solo bed is a fantastic option to maximize space and versatility. I secure it to the ceiling of my Adventure Wagon interior using the FVC cam straps and it works great. I have a cam strap at the top and bottom set to the perfect length to keep the bed level, and then a third strap in the middle that I can quickly tighten to fold the bed up out of the way and then loosen to drop it back down.