We have this mattress in both our home's bedroom and RV bedroom, in the King, 10" thick size. I've slept on many Sleep Number mattresses and I don't like them, but to each their own. Our RV came with a coil spring type mattress and we did not like it either, didn't take but two trips for us to order one of these for the RV. I don't think you can beat the price for a foam/memory foam combo mattress.
They do offer a California King.