I appreciate the replies. Nothing trumps field experience.
My experience with the Thermarest line over the last 20+ years has been stellar. With reasonable care they just keep going. The Neo and Mondo lines are on my short list.
I'll poke around in a few outdoor shops and see if the rubberized cotton air mattresses are still available. Or (being naturally contrary) I may try a patch on my existing one, if only on principle.
But it's not about dollars per se. A good sleep is the best medicine, and worth every last penny.
Thanks again for your help!