I've been playing with Vantage Leather grips lately. With poly, the leather is terrible. I feel all the vibrations and my rackets just feels like a board. I then switched to a racket strung with kevlar and instantly felt the difference. Gone was the vibration and the feel was much more solid. So far I'm not so sold on leather grips.
The Vantage leathers seem to be pretty thin though. So I'm curious what a thicker leather will feel like.
Pure Drive Roddick 2012 - Big Hitter Blue 17g - 54 mains/52 crosses