Mariner of the Seas receives generally positive reviews for its friendly and hardworking staff, enjoyable entertainment, and a variety of activities, especially for families. Guests appreciate the ship's amenities and the experiences at private islands like Coco Cay. However, some reviewers note that the ship is showing signs of wear and could use updates, and there are mixed opinions on food quality and dining experiences. Crowding in public spaces and perceived value for money are also mentioned as areas for improvement. Overall, most guests had a great time, but there are recurring suggestions for better maintenance, more attentive service in some areas, and improved food options.