There are a number of factors to consider when choosing a guest bed. Where it will be stored is important, how easy it is to fold up and transport, and of course, how comfortable it will be for the guests.
Camp beds are relatively cheap and can be stored away easily. They are usually constructed of a metal folding frame and a canvas cover- lightweight but not that comfortable, and certainly not that aesthetically appealing.
The most common answer is the fold-out sofa bed. Storage is a given because the bed masquerades as a sofa when not needed, and they rarely need to be moved because they are already in position. The drawback is that quite often they aren’t that comfortable as either a bed or a sofa- like many designs that try to do two jobs, neither task is well served. There is often a gap down the centre line of the bed or a saggy patch in the middle, and the metal bars of the folding framework can be problematic.
Futon beds arrived in the west from Japan, where they are the traditional bedding style. The simplest form is a padded mattress that can be rolled or folded away during the day to conserve space. The traditional cotton or fabric stuffed construction is thought to be good for the back, but is less yielding and soft than many modern mattresses. The fact they can be rolled is a distinct advantage for storage, but traditional futons do need to be aired regularly to prevent mustiness. They are also very heavy.
For the western market, futons are usually sold with a wooden frame of some kind, either to simply lift the mattress off the ground or to convert to a sofa. Because they are easily bendable, a folding, slatted wooden frame can form the basis for a neat unit that does both, with the mattress acting as both seat and back cushions. Such designs lack the intrusive metal bars and unpadded sections of conventional fold-out sofa beds and are an ideal solution.