I wouldn't buy it again
I'm a male in my 40s. I use the memory foam mattress directly on tatami mats.
When I first slept on it I had to change the way I shove my pillow under my head and neck; the first night my neck hurt. I did figure out a good pillow position, but even then, I didn't sleep very well and would wake up with little aches and pains. Every time I shifted my sleeping position in the middle of the night, the mattress took several seconds to re -contour to my body, which made me wake up because I would be sleeping on bumps for a few seconds. My wife couldn't even take a nap on it. After three days I went back to sleeping on two futons.
I guess from the reviews here that some people like this type of mattress. All I can say is that for me it was a waste of money. I sleep almost exclusively on my side (never on my stomach) which may have something to do with it. For the price it may not bad to test it out yourself, but.......
The mattress is a standard futon size and comes with a mattress cover. The cover needs to be hand washed, and isn't terribly high quality, so you'll want to have some fitted sheets to go put over it. You can use standard futon sheets. It is relatively light, and is easier to move around than a standard futon because it is stiff.
KEEP IN MIND This product ships wrapped up in plastic about the size of a medium sized duffel bag. It will become flat and usable after about 3 days in the winter. When I got it, I put it into a spare room, cracked the window and shut the door. It took several days for the mattress to stop off gassing and if I entered the room the smell was very obvious. After about four days the smell doesn't stink up the room, and you can only smell it if you do something silly like lie down on it........ Evidently this is the nature of memory foam, just realize that you won't be able to use this product for 3 days at a minimum (because of the shape), and probably longer if you are at all sensitive to the smell.