The Zanzibar cafeteria is open at breakfast, lunch and dinner. A buffet style which allows you to get what you want. You may be fighting for a table and in long queues (or bundles) with your food getting cold as we found it like a cattle truck. Therefore you may prefer the restaurants however you can be sitting in these for hours at a time if you decide to have all your meals in them.
For dinner in the evening you are allocated a set table and sitting (either 1st or 2nd - most english passengers found they were put on 2nd sitting as 1st sitting was given to other europeans and the english pushed back to 2nd sitting - we were lucky our request for 1st sitting when we booked was granted as passengers who wished to change when they got onboard were refused and told it was tough. People on 2nd sitting said they were coming out at 11pm most nights).
If you choose to have breakfast or lunch in a restaurant we were able to dine in either of the two restaurants as we had no set table assigned to us.
Beware water will cost you 2.30 a go and tea and coffee can be hard to find. Tea and coffee can only be had at the restaurants at a charge. Only during breakfast, lunch and dinner times in the Zanzibar you will be able to get one. This is not good for us brits.
After reading Brown's experience I suggest you read the reviews for this line/ship (big orange button) if you have not already done so.......Wilba.
For evening meals you are allocated a set table in one of two restaurants. You stay with this throughout the cruise. If you are not happy with the sitting, you may request a change via the Maitre D.
Breakfasts are open-seating in the two main restaurants or self-serve in the cafeteria.
Lite-breakfast in cabins is also possible at no extra charge. A limited room-service menu is available at other times on a pay-for basis.
Lunches are open-seating in the restaurants or self service in cafeteria.
Afternoon tea is self-service in the cafeteria.
Midnight buffets are either in the cafe or in lounges - see daily programme.
Speciality restaurants offer another choice, which has to be paid for.
I'm not sure what the procedure is for Yacht Club guests.
Hope this helps.
PS - We packed light-weight cups and travel kettle with adapter plug, together with sachets of coffee/latte. This meant we could enjoy drinks in our cabin whenever we liked. Just unplug the kettle when it's not being used.