Does anybody know which is better?

I'm looking into buying a round pen and have been told galvanized is better than painted steel, that is as long as the steel doesn't become exposed. I left a horse trailer in the pasture once to make it easier on me to practice loading and the horses started biting the fenders scratching the paint off and now they are all rusted. My husband says that powder coat is harder and they won't be able to scratch it off.Does any one have any experience with this? Thanks.