The original version.
I'm 6ft2in 189lbs . That mattress is for fairly proportional people. To a proportional person, the mattress is soft. A heavier person will push thru the purple layer and hit the support level and the mattress feels firm.
If you are outside that range, just pick the version for you. I'm pretty sure those other designs have the same effect.
The bed was a game changer for me. Just laying on it when in pain, can get a brief period of no pain, quite dramatic. It stays cool. It doesn't hold you like a foam one. Motion isn't relayed to the other person.