I use the BMBH from Jacksrbetter and it sleeps as flat as any hammock I've used. Very pleased!
While I can lay on my stomach, it isn't very comfortable for me @ 6'1" - maybe if I was shorter. Here's the deal for me: I can't comfortably put my arms above my head due to the length, and I can't comfortably leave them at my side due to the width. I'm skinny and it just won't work well for more than a few minutes on my stomach.
All that said, I've read some people's experiences that worked out well. You'll just have to try it to see since comfort is subjective.
-- Funny Money
Love 'em while you got 'em