We agree with most of the information provided in reviews contained in this forum but with less enthusiasm. I will add some personal thoughts.
The itinerary was fine but after seeing bluefooted boobies, sally lightfoot crabs, sealions, marine iguanas, frigate birds, lava lizards, little birds, for two days they all became somewhat old after that.
The contracted guides were excellent but Carlos and Marvin really stood out. The zodiac drivers had good skills.
The cruise director did little more than present a briefing on the following days activities and checked people off the boat on each zodiac event. He made no attempt to get to know any of the passengers.
Viewed two BC documentaries on the Galapagos during the afternoons and they were good. would have enjoyed more enrichment activities.
The food was OK and well presented but nothing really exceptional. The wines were very nice. Stuck with fish dishes most nights and it was tasty most evenings. Breakfasts and lunches were average. Sitting in the aftmost section of the vessel resulted in delays in eating dinner. Dinner should have commenced an hour earlier. I got really sick on the morning we disembarked, was it the lobster the previous dinner? Ran into some other passengers in Cusco post-cruise and they mentioned the same GI tract illness and they had eaten the lobster too. Maitre'd Fernando was extraordinary, likely the best I've seen in over 35 cruises, he couldn't do enough for us, very friendly. He did a nice job of organizing my wife's birthday celebration. He was the hardest working person in the crew.
Saw the Captain twice at the Welcome Aboard and Farewell meetings. He didn't mingle at all. Was not on the bridge when we toured it.
So glad we opted to do Cusco and Machu Picchu on our own post-cruise as we saved thousands over what Celebrity was charging even with staying at the obscenely expensive Sanctuary Hotel for one night. It was easy for me to put together a nice 5 day post-cruise land excursion package.
The snorkeling was poor (limited visibility) at best (was this bad luck or was it normal?), the Xpedition provided equipment was adequate. Opted not to try snorkeling the final opportunity because I had been so disappointd earlier and I understand I missed the best day of snorkeling. Perhaps I've been spoiled by really great snorkeling in the Tahiti area.
The cabin was fine and the attendant was wonderful. The beds were comfortable and the linens were fine but the bathroom was a bit on the tiny side.
Compared to our Silversea experience in the Antarctic on Prince Albert II (now Silver Explorer), Celebrity Xpedition comes in a distant second in nearly every category.
All in all, we had a good Galapagos cruise but I think 5 nights vs. 7 nights would have been ideal.