We hadn't planned to book Aqua Class but ended up doing so, made little use of spa but cabin was very nice well looked after by Lester. Restaurant was main benefit and it was excellent, food very good and portions small enough to eat three courses. Front of restaurant team were outstanding and Frederick serving a delight. Somellier Enrique a star and chose great wines for us. Ports / excursions were good and we loved most, as people have said Santorini was beautiful but overun. Entertainment was better than we expected and casino staff good, had a great time with some regulars on blackjack table. Even though ship was quite full we found it easy to find quiet spots if you wanted them. Whether you can justify extra cost just for Blu is difficult but on balance we think so. Loved our first trip on Celebrity and looking at our next.