We sailed on the Western Caribbean itinerary. We're Diamond on Royal and have sailed on Allure previously. We booked an aft Grand Suite on deck 11, which was labeled onboard as an Aqua Theater Suite for the 7-day sailing.
With the Grand Suite, we has access to the Suite Lounge and Coastal Kitchen. The plus was the ability to get free drinks (including bottled water) form 11am-11pm daily in the lounge. Dining room breakfast via in-room dining was also nice because the breakfasts elsewhere on the ship were terrible. However, Coastal Kitchen was nothing compared to Luminae, Celebrity's private dining room for suites. The menu changed only once, halfway through the 7-night sailing. The room was loud and was shared with the regular Suite Lounge, so it didn't feel intimate or high end. The staff was pleasant but there wasn't nearly enough staff. We ate there the first night and opted for specialty restaurants the rest of the trip.
Embarkation for suite guests was fast during the first phase (getting the SeaPass) but we had to navigate a sea of people when heading upstairs to walk on the ship. Signage was poor and the staff gave us the run around to find the suite embarkation area. Same thing when getting off the ship. We had to go out of our way to find the suite area to expedite customs screening. You get different answers from different staff members.