I'm with Desert Dog on this one. After you have refinished them once, just keep them clean and oiled and they're easy to take care of. The key is CLEAN and oiled. Because most of the oils these days have molecules that form a polymer after they've setup, you don't want to trap dirt in the oil as it wont wipe up next time you go to oil the wood. My vote would be for the teak over the fiberglass swimstep any day.
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)