Seventies tech, indeed. Using a 100% full waveless waterbed purchased in 1989.
No issues whatsoever, use waterbed treatment once a year.
With frame, heater, mattress pad, using high thread count cotton sheets. Total spent, $400.
Tested the Tempur-Pedic, Sleep Number, Select Comfort, etc. Would not change, if given one, for free.
Lie on one of these for 15 minutes, without changing positions, you will feel very H-O-T.
As Mark K said, like sleeping on a toaster/oven. Would rather spend the money saved, on my Trac.
I'll sleep much better at night, literally. :supercool: