Murphy beds have at most a six-inch foam mattress; they take up a whole wall or fold into a cumbersome cabinet and have to be completely remade every time they unfold. Plus, what do you do with the bedding?
I recommend a sleigh-type daybed. My wife and I can sit on each end of this one and be very comfortable. Lots of storage space below, also. It has a 12-inch Walmart mattress that is firm and extremely comfortable.
Sofa beds have come a long way from the crappy mattress on tortuous springs.
Yet, this one would still have to be completely remade with each use.
For guests, I recommend AeroBeds.
Or, really, this wouldn't be any more work than setting up a Murphy bed each day, and this could completely disappear each morning.