I know I only ride to and from the MoT centre every year, but the Grip Puppies last for years.
They don't hold the rain water any longer than your gloves do and they are UV stable so don't go all manky and crumble to nothing.
For me, the biggest plus is the greater diameter and this is a plus for me for two reasons:
Firstly, I find the K throttle to be very sensitive to the slightest movement and as my arms bounce, the throttle twitches, even with a featherlight grip
Secondly, my seven-year-old-girl-like wrists and hands don't like pressure and the foam really helps.