Before you decide on a "number bed," I'd recommend reading this link from Mattress Underground . I thought I wanted a Personal Comfort or Sleep Number as well. But I realized after sleeping on a PC in my son's guest room then trying a Sleep Number in store, that I needed to set them super firm to get my back aligned properly. If you think about an air mattress, your heavier parts not only sink, but then they push the air elsewhere in the mattress. Both SN and PC have one large air bladder. So while I liked the idea of adjustability, I sure wasn't going to give up spinal alignment for it. And when I thought about it, an air mattress would be my last personal choice for a support layer. You can get regular mattresses in split configurations so that's an option too. I'm a single sleeper, so I do understand that for couples with different needs, sometimes the compromises seem worth it for the adjustability. I'll add that my son and his wife have been very happy with their Personal Comfort beds. He slept on a queen for years that 's now in his guest room, and then they got a King PC when they got married. Answer from whywhatif on reddit.com