I've gone to Masaya Volcano and the City, and taken the Isleta Tour and both were really interesting and filled with pertinent information. I'm a curious person, but during and after both tours I had no questions because they'd all been answered. Gustavo was the tour guide on both and his sense of humor and love of his country was completely evident. Very flexible, intelligent and well read about the areas he shared with his groups of travelers. The Isletas tour I'll do every time I go to Granada.... seeing the birds from the boat was an incredible experience. Tierra Tours does a really good job at hooking you up with the types of experiences you find interesting at great prices. There are many choices and they even have a shuttle that goes and comes back from San Juan del Sur. Nice people.