We are shopping now for a gunite pool. Liner pools have always seemed to me to be too susceptible to damage. We don't have any pets right now but we used to have a Labrador that would live in the pool if we let her. I don't like to think what her nails would have done to the liner. Children aren't much better. Their nails are shorter but they tend to take all sorts of things into the pool and then use them in ways you never would have dreamed of. Fiberglass pools would seem fairly durable but more limited in choice of shapes and sizes than gunite. Having lived in Florida since 1956 I've seen what exposure to the sun does to fiberglass boats over the years. It doesn't render them structurally unsound but the gel coats often become crazed with small crack lines. This may or may not be the case with fiberglass pools and would probably only be a cosmetic issue but if I'm going to spend several thousand dollars on a pool I'd like it to keep its looks.