I have the p6 it's a nice mattress, not a bad sleep In fact I sleep a lot better on it then my king coil bed we had. But I think my my gel memory food bed was the best, but way to much to spend on another one. Now if your married or single and "fool around" the sleep number is not a good bed for that. It's two separate bladders, so one side is softer then the other so it makes it harder to be romantic. All in all it's not a bad bed. Find it locally and build the platform your self unless you can get free installation. The base is black plastic snap together. Almost like a rubber made shed.
My wife and I slept on one at a Radisson hotel a few years ago and we found it to be a very uncomfortable night. The bladders lost pressure during the night so by the time we woke up, we were pretty much sleeping on a box spring. I think they are a gimmick used to entice sales. A good quality mattress will provide a good nights sleep without the added complication and mechanisms that will fail in time.
never tried a sleep number bed but the wife and i are big fans of tempur-pedic bed. my gripe with the tempur-pedic is the weight. our kingsize 12" model weighs something like 400+ lbs.....the movers had a hard time with getting it up the second floor. also harder to change the fitted sheets....need to lift the corners....even just the corner is heavy...especially for my wife....but love it...love it....love it.