"Sleep number bed" is a loser

Described by my brother, after several years of ownership, as "two troughs separated by a log down the middle." Each party sleeps in their own individual trough, and never the twain shall meet, unless one party makes a considerable effort to fling their body up and over the high log and then risk crushing the other party beneath the sudden onslaught of their full body weight.

If you pump up the sleep number (the firmness is controlled by adjustable air-filled chambers) to higher numbers, you can get the level of the troughs closer to the height of the log, but the outer edges of the bed are still for some reason lower than the height of the log in the middle, so at this setting, you unfortunately replicate a Mt. Vesuvius, mountain-type effect, with the center of the mattress as the peak of the mountain, leading to an unfortunate effect in which each party is prone to slowly rolling out of bed and landing on the floor beside the bed during the night.

And best of all, this is an expensive mattress.