We did not have good luck with our Sleep Number bed that came with our new 2008 Monaco Dynasty. The air motor went out just after one year and was replaced by Sleep Number. A few months later, the wands would not show the number (we lived with it)... then one side would not hold air, flat as a pancake.
So, while traveling north of St. Louis in St. Charles, we went out and bought a 'real' mattress, a king Beauty Rest with a pillow top. What a difference!!!! We discarded the piece-of-junk Sleep Number bed in the dumpster and never looked back.
When we sold the coach, I replace our expensive Beauty Rest with a regular RV mattress from Camping World and exchanged an older mattress from home for the Beauty Rest.
Don't let the mattress make you not buy a good motorhome, the junky Sleep Number mattress can always be replaced by a real mattress.
Good luck,
MM.