Oceania Sirena receives high praise for its attentive service, excellent food, and comfortable accommodations, especially for those who prefer smaller ships. Guests consistently highlight the friendliness and professionalism of the staff, the quality of dining, and the well-maintained ship. However, some reviews note areas for improvement, such as inconsistent service in certain venues, limited dining hours, crowded buffet areas, slow internet, and occasional issues with excursions and itinerary changes. Entertainment is generally good but not always up to the level of other aspects. Overall, the Sirena offers a refined and relaxing cruise experience with a few operational hiccups.