Latitude impressed me when I went a few years ago. It seemed to be a genuine 'festival of the arts' with a wide range of interesting stuff from ballet to poetry as well as music, but without having to walk for miles like Glasto. Being family friendly the atmosphere was respectful even though the adults were happily getting merry. Showers were easily accessible, I've never been cleaner.
That said we've stopped doing festivals due to the cost, you can do a family holiday for less. It's hard to justify.

