Yep. We have had it about 3 years I think. The cover stays put no problem. And it has been washed (it zips in half so that it washes more easily) because the kids drew on it.

We put it up against the wall and pull it out before we do the up/down thing. It would stand to far away from the wall (maybe half a metre) if we didn't, and that'd be weird!

It's not at all hard to put up and down. Just a few clicks. But if you don't do it too often, you kind of forget which way to pull up and push down bits. But it's fine, you get there in the end and its not hard on your back at all.

We bought the storage box for underneath it and it is ok, but you can't get the box in or out without lifting the entire bed - not just the cushion lift up bit. So not as practical as I thought, seeing as I can't lift the bed itself my own.

Off the top of my head there were either three or four mattress options. We bought the mattress in the middle of the prices. Because like you it was more for the guests to sleep on than for sitting. The mattress has a zip down it. Not down the middle but sort of a third/two thirds split. I often think it must be a bit uncomfortable on the zip, but we have had many many people sleep on it ( my parents, my fil, even my sister and her partner and their cosleeping bubba) and everyone said its comfy. It is lower to the ground than a normal bed so maybe hard for elderly people to get up from.

I used to think people were being polite but everyone seems genuine when they say is a comfy mattress. We are pleased we spent extra on it. My sister stayed for six weeks!