We had a memory foam bed for a few years and it was great at first but once it the memory got too good (I.e. Our body indentations became permanent) it was junk to us. We switched to a mid level sleep number a few years ago and still love it.
Like adjustable seat pedestals for our boats, once I found my sleep number I rarely change it. If either of us moves at night the other doesn't feel it because we each have our own air mattress. They are separated by a thin foam barrier.
There is also no box spring but they do offer a modular plastic stand for around $300.
Also, they don't carry any inventory in their stores so you have to order it there and the best you can do, or at least that I could do, was take delivery the following day. They take longer to deliver it if you pay to have them set it up, i think the fee is around $200 but I don't know for sure since I didn't pay it. Set up was a breeze.
The lower end models don't have pillow tops, the pumps are loud and the remote displays the sleep number in increments of 5. Whereas the higher end models have pillow tops of varying thickness, quiet pumps and display the sleep number increments of 1 and/or display a series of hash marks around the bezel.
I think mine has a limited lifetime warranty which is in part contingent on us using the mattress cover that came with it or which we bought as an option (can't remember now). We have not had any problems with leaks but somehow one of the air hoses got pinched once which prevented the side the hose was on from inflating. It was an easy fix, just removed the whatever was sitting on top of the hose.
I know someone with the adjustable base and am confirming what it costs, she says it is worth every penny but I just can't justify spending that much to make my bed more like a hospital bed. A good bed no matter what kind of mattress it has will likely cost several thousand dollars but if you spend 1/4th of each day (6 hours at night actually) in bed the cost is easy to justify, for me anyway. It definitely helped that my wife likes the bed as much as I do. Too bad sleep number doesn't offer a trial period like sleep train does (100 days according to try local,radio station).
Good luck and have fun shopping. Speaking if which, Our sleep number store is in mall. I remember laying down on each model, fully clothed, midday with my wife In various positions (on my left, right back, belly), spooning, in the center of the bed, on each side, etc. I was self conscious at first, until I realized there was a small line of people/couples waiting behind us to do the same thing. It's a big (four digit) purchase after all.