ceriths are awesome. They eat everything, bury themself in the sand in the day, flip themself over and dont get too big.
IMO, mexican turbos are highly effective but they're a pain in the butt when they knock things over, topple rockwork, fall over and sometimes die.
Right now i've got two fuzzy chitons and i'm loving them, they do real well on the glass. They dont' eat too much but they're pretty small and my crabs cant figure out how to kill them.