Thin Memory Foam Mattress - Looking for experience

[CaptTom]

I know mattresses have been discussed before, but I'd like to know if anyone has any specific experience with one particular type of mattress.

I'm looking at this 4-1/2" thick foam sleeper sofa mattress. Memory foam on top, "support" foam on the bottom.

I need something this thin, due to a very low clearance over the head of my aft berth. It sounds just right, but it'll be on solid wood, unlike a sleeper sofa. I'd prefer to try it out before buying, but that's not really practical.

So, I have a very specific question; If you've tried one similar to this, how do you like it, and why (or why not)?