Service was a highlight, truly professional and engaged staff. I got locked out on my balcony one day when we were in port(thanks to my absent-minded sister), and had to yell and wave for quite awhile no passengers were apparently around on a shore day and finally got the attention of a work crew down at the other end of the ship they came running and had me rescued. Thank you, gentlemen!
Celebrity did especially well on little but important things (for example, "real" dishes at all meals, no announcements inside the cabin which can be so annoying especially in the morning). The coffee in the main cafe was not brewed but instead made from a powder and some of my family didn't like ityou would however get the real thing in the dining rooms and from room service. Food was abundant and overall delicious (delicious ice cream bar was no charge!). Unlike other ships I've been on, it was always easy to find a place to sit even at busy times. Food was served by the staff more than serve yourself (Caribbean Princess, also a great experience, was more serve yourself at breakfast and lunch), but this kept the lines moving and probably resulted in a cleaner ship. There were a few dishes in the dining rooms that I didn't like, eg, a spinach turnover appetizer that tasted like it was from a frozen food box, but overall food was excellent. The made-to-order pasta bar, which seemed to always be open, was wonderful. I started a stampede one day when I had garlic added to mine and the most wonderful aroma drifted about.
We were in a suite which came with a great balcony, big bathroom (incl. bathtub) and butler service. Butler service was a nice treat but almost too much. The butler brought coffee/tea and appetizers every afternoon. We had the early seating at dinner and it was just too much food, as it's hard to turn down those appetizers! Other suite features were totally worth it: bigger room/bathroom, big balcony, spectacular views of sea and ports, complimentary champagne on first day and it wasn't that yucky sweet stuff.
Sales efforts overall were unintrusive and helpful (eg expo on first day was reactive rather than proactive). On the sail day, the bar staff seemed especially interested in putting a decorative drink in your hands but this was the strongest selling pressure I experienced.