I like the metal for the extra mass, and the grip fits me a bit better than the wood. The wood riser grips are a bit to small and to high of a wrist. They put my hand in a position to close to the arrow... I know there shouldn't be such a thing, but the feathers of my arrow give me notice that there is right in the web of my bow hand between the thumb and first finger at the shot.
If you have pretty small hands it shouldn't be much of a problem, but for me it is with the wooden grips.