I really depends on the horse for me. I have several differant cinches. My barrel mare has always done great with a neoprene cinch, but I had a little palomino filly who would ALWAYS get sores with any kind of neoprene touching her skin. It didn't matter if it was a pad, cinch, boot, blanket, etc. So I used alpaca string on her. But I had another who just seemed to really like wool cinches.
To each horse his own preference.