We traveled with a family group of 14 and everyone had a great time. Many more positives than negatives.
We loved the itinerary, allowing time on Maui, Kauai and the big island. We rented cars in all three places and did our own touring, rather than do the boat excursions. Some of our favorites were Waimea Canyon, the road to Hana, the port town of Kona (only place we didn't have a car), Volcanoes national Park, and the Old Lahaina Luau.
On board, our group had two balcony cabins and four inside cabins. We really loved our balcony units - we purposely chose the units on the port side with the larger balconies (89 square feet) which allowed room for the rest of the group to view the Napali coast and lava flows with us.