For our Cotopaxi climb we choose Gulliver. It was a good decision: very well organized, good guides (William and Jose) that knew what they were doing. Hostelleria Papagayo (same owner) is also highly recommended and a good base for climbing in the area. Transport to the climbing locations, which sometimes is hard to get to and need a good knowledge of local roads, is in good hands with Gulliver. And all this at a reasonable price! We enjoyed our stay in Papagayo, and the walking with the dogs and manager Raoul doing and excellent job making us feel at home. I planned on doing the lower peaks privately and only Cotopaxi with Gulliver, but I am very glad that I booked the 7 day package! Highly recommended. We rented a car in Ecuador, but that was a bad decision as taxi's are cheap and you don't have to worry about finding your way.