Do you think that sleeping on the floor is good or bad for you? Also, what do you think of other non-traditional beds (i.e. water-beds, hammocks, etc)
sleeping on the floor isn't good for me. I had a waterbed in the 80s and hammocks don't work for me because I don't like sleeping on my back.
From a body alignment point of view, a thin mat is enough as long as one's neck is kept in a neutral position. I slept on a 3 inch cotton futon from 1989 to 2011, and I'd go back on a second.
I slept on a futon on the floor from the mid 70's until about 6 years ago when I got a futon on a bed frame. I moved to the bed frame because I can get out of bed easier with my arthritis. I never tried a waterbed because I don't want to sleep on something that moves. I will probably stick with the futon for the rest of my life.