We did both last November when we stopped in the Azores. The ship's tour was well done. We were on a large bus. Our tour guide was a local gal who was very informative. On another island we took a tour through the big box agency you referenced. There were five of us-three from the ship and two from elsewhere. We were on a 4x4 jeep that went places that a large bus couldn't go. Our driver/tour guide was very informative and would stop whenever we saw a great photo op. We also signed up for a private tour through our roll call on a third island. There were seven of us in a van with a driver/tour guide. That tour had the most flexibility and value. In our opinion, all three types of tours were worthwhile.