Review about Galapagos Islands
1) Make sure you take a boat with a decent itinerary around the islands ie one that doesn't have to double back on itself. I personally think that the best ones are those that do a loop around the outer islands which is to say, around the western side of Isabella.
2) Please try not to bother going for less than 7 nights.
3) Bigger boats....98 passengers might not sound like a big boat but you watch a dozen zodiacs landing all at once in this environment and it's like D-day. If you can live without captain's cocktail hour and chandeliers then go for a smaller boat - 16 passengers is great.
4) See if you can go for a locally owned boat - these tend to source more of their provisions and more of their staff from the islands themselves (rather than Guayaquil on the mainland) which makes the whole thing more sustainable.