Hi, we went on the Explorer a few years ago and had the pull out sofa-I was going to sleep on it with my younger daughter. It was so bad-not supportive, wavy like underneath it had straps to hold the mattress in place and it was not very solid for support. I asked my room steward to bring in two twin size mattresses and put them on the floor and we slept like that , it was very comfortable. You just had to get up from the floor. We were able to accomodate the extra mattresses because we had a handicap balcony room and it was huge! Hope this helps.
The sofa is not good for adults. Our two little kids did fine on it, but I don't think either my husband or I could have slept on it, it wasn't long enough for one thing and doesn't lie completely flat for another.