I had one custom made for me when I moved back to the states. I think I had it stuffed with cotton. If I remember correctly, the ones I had in Japan were stuffed with wool. I remember I had to hang them outside when they were new for like a week to get rid of the smell.
I've been using it for about a decade now. I love it. My wife likes it, too. That's always a plus.
My parents, when they visited me in Japan, were nervous at first about sleeping on the futons, as my father doesn't have the best back. However, they slept well and were pleasantly surprised at how nicely they felt.
