I have some pretty vivid memories of the sleeper sofa from when I was a kid
It still baffles me why it took people so long to come up with a modern sleeper sofa design. The sleeper sofa that we have in our living room is practically as comfortable as our mattress bed. It is an extremely simple design. Basically, it is somewhere halfway between a couch and a futon. Rather than using heavy, hidden metal mechanisms, it uses lightweight wood components to fold down and up. You can set it up in a minute, and put it away just as quickly.
I have to say that it was a great investment. Before we got a sleeper sofa, we had to keep a bunch of extra mattresses around. You see, I am a musician, and as such I always have people coming through town. I play with a lot of different guys who like to stay over at the house to save money on hotel rooms. Back in the day, we would have to keep a store of cheap single mattresses in the basement. Every time the guys were coming over, we would haul them out and cover the living room with them. Nowadays, between the sleeper sofa and the futon, we don’t have to do any of that. Both of them are perfectly functional as daytime furniture, and easily convert into beds at night.
If you are living with a limited amount of space, I highly recommend a sleeper sofa bed. All of my friends who live in small apartments swear by them, because they allow them to have a couch and a bed at the same time. From the point of view of trying to maximize your available space, it just makes more sense.