I've got a bad back.. not just the "I got a bad back" that everyone complains about when they wake up stiff in the morning, but for real military injury long-standing bad back business. I bought into the hype and spent the $$ on a sleep number setup with the adjustable base and all the bells and whistles a little over 2 years ago. We've each had that thing at nearly every setting under the sun in that time and has been consistently the worst thing for my back. An expensive and glorified air mattress is still just an air mattress I guess. Tried multiple mattresses at various furniture stores, and what can you really tell about one in 90 seconds other than if it flat out won't work off the bat... Wife talked me into trying a Helix boxed mattress and so that's what we did about 60 days ago. BEST thing I've had since we had a Sealy 20 years ago that was a certain feel on one side and firmer on my side.. worked good for awhile but set up like that there's no flipping it over, so once it wears in to your body shape, it's over. We went with the Helix Luxe midnight I believe is the name, and went for their cooling pillows too. So far, anything "cooling" I've tried seems like a gimmick.. these DO feel cooler to the touch when not using them, but I can't tell any real difference once I have had my head on it for a few minutes. 
That being said, the mattress, paired with their base, has been a game changer for me to this point.