We have only had our pool (gunite) for 2 years, so I'm no expert. I've never seen and heard of a gunite pool shell failing from friends, neighbors or a couple of very informative web forums. ShotCrete may be technically better but doubt it would ever be an issue on a properly constructed pool. Plenty of talk about decks cracking or heaving, plaster failing, plumbing leaks, drought and famine :-).