This was our third cruise, and our first on Celebrity. We selected Celebrity because we heard that it was a bit more "refined" and I think it's safe to say that was the case. There were very few children/families on board, although the families I spoke with were happy with their accommodations and services.
We boarded early in San Juan - we'd spent the night before the cruise in town, so we were at the ship by about 11:30am and on board shortly thereafter.
Our room, cabin 8115 was a 'Concierge Class' cabin with some additional amenities. Overall we found our room to be much more spacious than on other ships we've sailed (Carnival and NCL) with a great deal of storage space. The Concierge Class had some additional perks like upgraded bathroom fixtures and linens which were a nice touch. The daily canapes delivered to our room were OK but could definitely be upgraded. Our cabin steward was very thorough and prompt, and kept our room looking wonderful. The concierge class cabins also have a more comprehensive room-service breakfast menu, although we preferred to eat breakfast elsewhere since the room service food was not always the right temperature.
Don't sail on Celebrity if you are looking for spectacular shows or wild night life - you won't find either. We were cruising more for the destinations and for relaxation (time away from our small kids). I visited the spa several times - don't book spa visits right away as they will have daily 'specials' at much better prices each day of the cruise.
The food aboard the Summit was wonderful. We dined at the Normandie our first night, which was fine but not as 'spectacular' as others have commented. This could have been because it was the first night of the cruise and most people were dining casually as they didn't have their luggage yet (by the way, priority baggage delivery is part of the concierge class package too, and our luggage was delivered within about 2-3 hours of boarding the ship, when many others did not receive their bags until just before bedtime). The main dining room food was delicious and was served well. One of the things I really appreicated was that there was a good variety of healthy food available throughout the day, both on the main dining room menu and at the Aqua Spa Cafe. There was also ample un-healthy food available, with hot dogs, burgers and nachos available most of the day at the poolside grill.
Another 'secret' is the Waterfall Casual Dining option available at dinnertime - this is a small restaurant where waiters-in-training are trained. They have a different menu than the main dining room, and a whopping $2 cover charge will get you a nice, quiet meal (a contrast from the more chaotic main dining room) of the same caliber as the dining room. Try the black bean soup - I thought it was wonderful!
PS - I've read other reviews commenting on the coffee served on Celebrity. Those reviews are correct - I don't know if they use the darkest roast known to man, or if they use twice as much coffee as they should, but the stuff is STRONG - so much so that it took a great deal of cream and 2-3 sugars to make a single after-dinner cup palatable. Let's just say that I had coffee with breakfast and never yawned all day!
The pool area was relatively small compared to other ships I've been on, however, there were many lounge chairs that were shaded, which was nice for a fair-skinned Midwesterner who burns easily!) All of the chairs on the pool level were cushioned, and there were towels and pool attendants everywhere. The gym was impressive with many elliptical machines and treadmills, as well as a good selection of weights and other equipment.
The service aboard the Summit was wonderful. Everywhere I went, there was someone dusting, vacuuming, or cleaning something - and when you pass by, they go out of their way to greet you and wish you well. The staff also seemed to be very proficient in English as well, which I have not always found on other cruise ships. I did not see any significant signs of wear and tear on the ship - overall I thought it seemed to be in good shape.
I would definitely cruise with Celebrity again - if you are looking for a relaxed atmosphere with good food and great service, this is a great cruise line and ship.