I really liked the National Geographic Endeavour. It wasn't luxurious like a Regent ship but it was very comfortable, had great character and an amazing staff. It just seemed right for a trip like the Galapagos which really isn't so much a cruise as an expedition. The food was fantastic, they made use of local seafood, great products grown locally or from mainland Ecuador and presented local dishes at just about every meal. The cabins were small and the shower was tiny! They were quite functional though and the room stewardess was in to freshen up the cabin at least three times per day and you really spend no time in the room other than showering or sleeping. The toiletries were in dispensers but were of high quality (organic Kiss my Face). I can't say good enough things about the staff. The naturalists were top notch. The shipboard staff were extremely efficient and accomodating. Lindblad supplies most of the equipment you could need; snorkel gear, shortie wetsuits, hiking sticks, Wellies for the day hiking in the muddy highlands, waterbottles etc. There was an onboard wellness specialist who lead exercise classes and did great massages. There is an onboard videographer who compiles a 30 minute DVD of the trip (both above and below water). My ONLY complaint was the internet service was extremely slow and expensive. I wouldn't bother with it next time. I would just wait until the day in Puerto Ayora when you can get 30 minutes of high speed service for $1.25 at one of the several cafes.
You do have to have good mobility for this trip. There are no elevators on the ship, getting on and off the zodiacs can get challenging and many of the hikes are over really rough volcanic boulders. There is always an easier option for the hikes and they have a glass bottom boat for those who don't want to snorkel.