Futons are a sort of a modified form of a sleeper sofa. They were pretty popular a while back, but I don't think they are, so much, anymore. Maybe, I don't know. I have had a couple of them. They look reasonably okay, they are cheap, portable, and they work okay as a couch. Not so much as a bed. At least the ones that I had and a couple of others that I have slept on while staying over at people's houses. Maybe for young bodies, they are okay. I can remember when I could sleep on a hard floor without difficulty. But these things tend to have a bar in the middle of them that becomes increasingly painful as the night goes on. Plus, the padded parts are usually pretty thin. I suppose some of the more expensive ones might be okay but then I'd probably look at another option.
My daughter had one I think in Dental school. Ive slept on it, not too bad but I was younger then.. Think my son also had one, slept on that one also. If I ever have to live in a studio apt, I would probably get a comfortable one...pull out sofas are less comfy in my opinion.
Ken, I slept on a REAL futon for two years when I lived in Japan. It was a simple pad on the tatami floor that was rolled up and put into a closet every morning. As I recall, it was quite comfy, but I was much younger then.
For over twenty years my bed was a two inch thick twin size foam pad with sheet and covers, then about 15 years ago I wised up, and did an overhaul. Since then my bed has been a High Density 6" inch High Quality Memory Foam Queen Size Mattress /w zip on cover. On top of that is two goosedown featherbed mattress toppers, similar to this ~ https://preview.tinyurl.com/yclerphn Then another mattress pad. Over this a fitted real silk sheet. Then covers. I've taken my bed seriously as you can see, and now love waking up in it.
I've had a proper Japanese futon, and also a good quality thick upholstered sofa type futon...I'll see if I can find a generic picture of one the same...... Looked like this but it was in blue & white check...
We had one for our guest room and our girlfriend used to complain about it all the time. We ended up giving it away and putting in a single bed and a loveseat. That worked out well for her since she only stayed a weekend or two each month.