M.L.
My brother had one and gave it to my grandparents for their guest room. It wouldn't be something I use every night, because putting it away every morning would get annoying (like a trundle bed), but for vacations or guests coming over, it can be very nice. Some futon mattresses are cheap and uncomfortable, others are pretty nice. The one my brother had was really good quality. So, it just depends. You can always trash the mattress on a craigslist find and get a new one.