As already mentioned, Bella Vista is the exclusive restaurant for suites. For dinner you will always have the same table reserved and they will tell you what time they assign you dinner. For breakfast and lunch you can go at any time during opening hours and they will give you a table depending on occupancy.
Regarding room service, I only used it to order breakfast and it was fantastic, the presentation, the quality of the food, superb.
And yes, drinks from the minibar are included. They replenish what you consume daily. There is water, juice, soda, cold tea and beer, if I remember correctly. And ther is also a nespresso.
We really enjoyed the experience, not only because of the suite itself, but also because of the exclusive area on the deck, with sun loungers and a jacuzzi. In August the ship was overcrowded and having that exclusive space was incredible. And of course, the friendliness of the waiters and the quality of the food at Buena Vista. Nothing to do with the MDR.