A year ago I bought a Charles P. Rogers mattress and am really pleased with it.
Charles P. Rogers Powercore Estate 5000 mattress - Consumer Reports
I also have a three year old Hotel Collection King from Macy's which I like but I prefer the Rogers mattress. Mine are Eastern Kings. I don't know if Rogers makes a California King if that is your preference. I like the slightly wider bed and don't need the little extra length.
Your mattress choice will depend on your weight and in what position you sleep. I am 6'2", weigh 220 and sleep on my back. Some mattresses do not accommodate well a person weighing over 200 or a side sleeper. My girlfriend, 5'9' and 125, finds the Rogers a little firm, and prefers the Macy's mattress. My back is good with the Rogers and OK with the Macy's. When a mattress starts to sag my back lets me know it is time for a new one.