Choosing a mattress is a totally personal experience, and different people will prefer different options. Basically, you want to pick one that allows your spine to be straight in every position, so it's in the same position as if you were standing straight up, just without the pressure on it. For heavier people, this means a firmer mattress that doesn't sink with their weight (if you feel like you're sinking in, it's too soft for you). For lighter people, this means a softer mattress that doesn't push back against them. (If you're in my vacation bed, it might not matter how heavy you are, since I believe that mattress was designed to resemble granite). But I imagine that some people just prefer a harder or softer surface, regardless of these guidelines.
So what did you pick, and why? Are you happy with your choice?
Images: Schramm; Duxiana.com
Related AT posts: Maxwell's Year in Bed, especially Some Things I've Learned So Far