Firstly, don't mistake the itinerary with the quality/treatment of the actual cruise line. One cannot fault the islands or weather and this ultimately says whether you had a good holiday or not.
Secondly, the waiters/waitresses and cabin boys etc.. are all lovely people who are very friendly and this applies to all the cruise lines. After all, they take from the same pool of people.
My comments merely apply to the 'management' of Celebrity and their attitude to their customers, irrespective of the veiled smile that is trained into them.