I tried one and my very sensitive TB couldn't stand it the moment I got on, his back came up like a banana and I had to ease him into a corner so I could dismount before being ejected!!!
I found it rather thick - made my well-fitting saddle pinch. I also thought it was VERY expensive (didn't pay for mine, I reviewed it for a magazine) and it dyed my horse! My coloured mare had orangey-pink bits for weeks.