I used to use Babolat leather on my EXO Tours, but have since switched back to the stock synth grip. I like a less headlight balance a bit better.
When it comes to synthetic grips I prefer Prince Resi Pro (stock on the EXO), Babolat Syntec (stock grip on a Pure Drive) and Babolat Skin Feel (for reduced width and weight).
If you want the feel of leather (with overgrip of course) without the weight then try the (kinda newish) Head Synthetic Leather grip.
Prince Tour 100T ESP \\ Prince Tour XC 15L