If you own a fiberglass boat and use it hard, gel coat repairs will be part of your maintence plan every couple of years so just expect it. Treating a metal boat the same way will eventually leave you with dents and/or obvious scrapes.

Fiberglass IS easier to push over rocks.

In the end, if you own a good boat (either metal or fiberglass), you will like it. I like my Clacka. I like Coley's Willie boat.