We had a great time; last year we were on the Galileo and this year on the Harmony G; (next year Cuba).
The Harmony G is a good ship with a good lay-out. There is a nice deck in the back but you cannot walk around the boat outside or go outside in the front of the boat (on the Galileo you cold walk around the boat outside and had a lot of outdoor space and we liked that better)
Having been to Greece the year prior, we explored on our own this year and were off the ship most days right after breakfast and returned after dinner. We wanted to get as much of the local culture as possible. I did extensive research on Trip Advisor and looking at Google Maps to see the areas we were going prior to leaving home. The islands are friendly and easy and fun to navigate.