Oceania Sirena receives high praise for its attentive service, excellent food, and intimate small-ship atmosphere. Many guests highlight the quality of the staff, well-maintained cabins, and diverse itineraries. However, some reviews mention inconsistent service in certain areas, crowded dining venues, and disappointing excursions or missed ports. Entertainment is generally good but not always up to the level of other aspects. Pricing for excursions and specialty services is often considered high, and internet connectivity is a common complaint. Overall, the ship delivers a premium experience with a few areas for improvement.