Everyone in our large group had the app, and it made connecting with each other on the ship very easy. The chat worked well (a few delayed messages, but usually it was immediate), we loved the activities listing and ability to "favourite" and get notifications as well. The deck plans were handy, and the descriptions of shows and activities were excellent.
Disappointed that the menus werent up to date (tried to plan ahead for picky-eater kids and plans were foiled when their chosen option wasnt available!)
The kids club activity centre still uses the wave phones (available in your stateroom) to contact parents - should integrate their texting into the app so that we didnt have to carry around an extra phone we never used.
Suggestion:
The app should include access to the pro photos taken on the ship and be able to order from your phone.
sjroom about Disney Cruise Line Navigator, v1.4.1