My 5 and 9 years old girls loved it, the pool and the short walk to the bay with their thermal waters was the main attraction. We ate beautiful pizzas and salads at the snack bar, and the drinks were reasonably priced.
But getting there and out with public transport was an odyssey, absolutely horrible, specially with the children.
They do shutter buses from the hotel to Panza, where you can get the bus to other locations, but again, be mindful of the crows and the heat in the local buses!
Sant'Angelo was beautiful, but there was only private beaches and no nice areas for the kids to play.
Overall our stay in Ischia was definitely positive thanks to Castiglione and their crew.