Mariner of the Seas receives generally positive reviews for its friendly and hardworking staff, enjoyable entertainment, and a variety of activities, especially for families. Many guests praise the food and the ship's amenities, as well as the private island experiences. However, some guests note that the ship is showing signs of wear and could use updates, and there are mixed opinions on food quality and value for money. Crowding in public spaces and extra charges for specialty services are also mentioned as drawbacks. Overall, the cruise is recommended for its fun atmosphere and service, but some improvements are needed in maintenance, food variety, and pricing transparency.