I use gloves sometimes. Don't wear them so much for grip improvement, rather to reduce lead exposure. I just use gloves picked up at Home Depot for about $10, that way I don't feel badly when they start to get holes in them.
In the winter/colder months, I wear Specialist All-Weather Shooting gloves by Hatch.
I also put Agrip by Brooks Tactical on my G30SF. They work really well. The wetter your hands get, the gripper/tackier they feel.