YMMV. Whenever I have had my mattress on the floor, (a) the dust at floor level drives my asthma batshit (b) it's harder to get out of bed in the morning (because I need to lift my centre of gravity higher), and I have enough trouble convincing myself to get up.
I have often benefited from recommendations for Things I Didn't Know I Wanted.
Given that Less Wrong is a community of unusually intelligent, critical, and self-improvement-focused people, I suspect we can generate a pretty helpful thread of product recommendations — perhaps even a monthly thread of product recommendations.
Rules: