One of the apartment complexes I worked at had Murphy Beds. There were about 20 Efficiency Apartments with an unbrand Murphy Bed. They were in the 20 year old time frame, and the mattresses were pretty lumpy, but my hide a bed sofas are much worse.
The only maintenance issue I saw was at the fold-up pivot point. If there were a few people of good size really bouncing or maybe jumping, they could damage that pivoting mechanism.
The other thing I noticed was, people would have things spread across the bed (Think paperwork) and someone must have shown up, they would fold up the bed and the paperwork would slid to a compartment inside the framework and required minor disassembly to gain access. During clean up I often found one to three sets of pillows and numerous books!
Ivan