Mariner of the Seas receives generally positive reviews, with guests praising the friendly and hardworking staff, enjoyable entertainment, and a variety of activities, especially for families. The ship's private island, CocoCay, is a highlight for many. However, some guests note that the ship is showing signs of age, with outdated cabins and worn public areas. Food quality receives mixed feedback, with some enjoying the dining options while others find them repetitive or lacking, especially for those with dietary restrictions. Crowding in public spaces and pools is a common complaint, and some guests feel the cruise is becoming too commercialized with extra charges for many amenities. Overall, the cruise offers a fun and relaxing experience, but there are areas for improvement, particularly in food, maintenance, and value.