I developed my carbon grips over 8 years ago, not looking for style but well for performances. It has proven to be a wise move as the increased sensitivity and feel are a big plus for fly rods.
You can feel your blank loading and unloading while casting, you actually feel the type of substrate your nymphs are drifting over (grass, gravels, rocks). The strike detection is faster, giving you better hookups and less chances of unhooking a fish. A true plus!
Important notice: these carbon grips offer a great grip and do not slip even when wet, in the contrary!