have got a gath surf convertible , honestly don't even realize it is on in the water .
reasons I got mine same as supanimal , keeps ears warm ( much prefer the helmet to the hood ), keeps hairless head covered ( have got a visor on it ) ,gets the wife off my back when surfing alone

and really it is common sense , its too easy to get a smack in the head .
we had a fair discussion on this in the 666 forum recently , some thought those wearing helmets were risk takers and a danger to others , WTF
I have the bright yellow one , pretty hard to miss