This rolls into a small space when not in use. It's not as comfortable as you might be used to in a real bed, of course, but I made a point of sleeping on it one night before using it for guests, and I was completely okay with it. I am an average size woman and I imagine a larger person might find it less comfortable. If you know someone is coming try to set it up a few hours early so that the memory foam can fully recover from being stored in the folded position.
We purchased this bed for "overflow" guests. They all have commented that the foam mattress was surprisingly comfortable and allowed them a good night's sleep. It also works great at the bottom of our bed when young grandchildren visit.