We stayed in a one bedroom unit at OKW last week. The king mattress in the bedroom was fine. However, the sleeper sofa was very uncomfortable to sleep on. We had unexpected guests our second night (their reservation got messed up), and we gave them the king bed (respect for our elders!). I woke up with such a backache in the morning. I opened the sleeper chair and finished resting there. The chair's mattress was thicker and a bit more comfortable. Both were very hard though.