In the interest of full disclosure, my wife and I are not big cruisers. We travel extensively, but have only done a few cruises. Generally, we find them underwhelming.
Celebrity's Xpedition in the Galapagos is an exception and we would do this trip again in a heartbeat. In a word it was fantastic and crushed all of our other cruise experiences.
You will not find a better way to see the flora and fauna of this unique part of the world. The staff, Zodiac drivers, and naturalists see to that. I knew we would get up close and personal with animals, but never in our wildest dreams did we think it would be this close. How many times do you have to zoom OUT to get pictures of animals? Never, but in the Galapagos - yeah, you do. This is, of course, your reason to go and you must go. If this isn't on your bucket list, add the Galapagos today and I don't see how anybody could handle making that check mark any better than the Xpedition.
As I said, on the small side, but perfectly adequate. This trip is not about the boat. We were perfectly comfortable and our steward kept our room in great shape.