The "Tourist Superior" class rating of the Samba is accurate. A well-maintained ship, excellent crew, very knowledgeable guide, well-prepared food, extremely clean and good quality accomodations, but not a super-spacious boat. You spend almost no time in the cabins, so a clean and comfortable bed is really what you need, and Samba provides that amenity. Our guide, Nic, was spectacular. He was very knowledgeable and spoke excellent English. We were very happy with Nic, even though he is not the everyday Samba guide (the regular guide is part-owner, and has a good reputation too, but had the week off when we traveled). The trip has a heavy dose of both snorkeling and easy hikes, and some kayaking. If you do not like snorkling, you should pick a different boat, as half of the excursions are snorkeling excursions. The marine wildlife is just as amazing as the land creatures, so we thoroughly enjoyed both activities. 

I am 6'4", so I can speak to the bunk-size question asked by one of the forum participants. The boat has 6 double-cabins, and one larger suite with a queen bed. I stayed in a cabin alone (my boys shared a cabin). All cabins (except the suite) are bunk beds. The lower bunk bed of the cabins is quite comfortable for a taller person, if you sleep slightly diagonal (the lower bunk is much wider thant the upper bunk). The suite is on the top floor of the boat , and sounds great, at first, since the bed is very large, and you have a relatively private balcony. However, since the suite is at the top of the boat, the movement from the waves is substantially higher. If you are prone to sea-sickness, you will have a problem, so avoid the suite if you don't like ship movement (almost everyone had seasickness at some point during the trip, since the waters are rough, especially on the overnight journeys). The six standard cabins on the boat are "at the water-line", with port-hole window, so movement is much less than the suite.

The Samba is a single hull boat , so expect the vehicle to sway. The northwestern itinerary has some long overnight legs, which sounds good because you can sleep during these times. However, do not expect a restful sleep during the long journeys because the seas are fairly rough. The rough seas dynamic is a part of cruising in the Galapagos, so all boats face the same challenge. We did speak to many people about the single-hull versus catamaran debate: catamarans may sway less due to the double-hull, but the banging of the waves on that double-hull of the catamarans are just as big a challenge for sleeping as the movement on the single-hull. Pick your poison, I guess.

The boat carries 14 passengers, plus the crew. We found this size to be very convenient, as we could get to the land and sea excursions very quickly (the Samba has two zodiac-style inflatable boats). Apparently, getting on and off of boats with more passengers can be a time-consuming event. We never had a problem with the Samba. Everyone eats in a common dining area, which is also quite comfortable. The boat is large enough to have some good private areas too, for those times you want to be alone.

We really enjoyed the Samba, and would travel with them again.