i'm not going to embarrass posters individually, but obviously some people contributed more helpful recommendations and reviews than others.
good mattress:
old 40+ year old
all
simmons memory foam
serta icomfort memory foam
sleep number (claims disputed)
doubleupsforbeds
stearns & foster estate line plush (cal king only)
memory foam (any, cal king size only)
fancy ass, adjustable 5k memory foam
expensive, stupid comfy couch
any (king size only)
normal pillow top (claim disputed)
no matter (cal king size only)
simmons beautyrest pillowtopped w. 4" memory foam
good
tempurpedic (claim disputed)
quality brand memory foam
bad mattress:
sleep number
tempurpedic
crappy one-sided pillow top
terrible crap