We are platinum on
DCL and Diamond Plus on RCL. We love sailing in the RCL suites (Grand Suite minimum, don't bother with Junior Suite).
Dining rotation is only a DCL thing. No such thing on RCL. In the Main Dining Room, you can book early seating, late seating or My Time Dining. MTD simply means you dine when you want to that day. Reservations are suggested.
If you are sailing on one of the Oasis class ships, then you may not even darken the door of the MDR as suite guests have access to Coastal Kitchen for all meals. On a 7-night cruise we typically sail in a suite and book specialty dinners 3 nights.