Wood is for looks, rubber is for shooting.
On a GP100, I'd probably lean Hogues. On Smiths, I prefer Pachs because I can't stand the exposed backstrap. Pachs tend to feel sloppy when first installed but "settle" after a little use.
As someone previously mentioned, if you can find the original GP100 grips, they beat Hogue, pachs AND wood. Best factory grips ever.