We cannot say enough good things about the Bonora Country House. The hosts are very dear people, the attention to detail in and outside the apartment is amazing, they really thought of everything you could possibly need, and a few things you didn't know you would. Finikia is a great location, really good restaurants, winery, and 20 minute walk to Oia. We ate at Krinaki 3 times and Finikia's Place at the Finikia Memories Hotel twice, wonderful people wonderful food. While you could spend your entire time in Finikia, we suggest you rent a car and explore the entire island. Akrotiri ancient site is very interesting and the St. Ilias Monastery is very much worth a visit, if only for the view, but hike the trail, you won't be disappointed. Oia, while pretty, is so commercialized it was like visiting a Greek Epcot, we went once. The sunsets from your own patio, or down the "street" past the Heliophos hotel in Finikia, or from Finikia's place are better because there aren't the crowds, and it seemed to be the same sun. This time of year was great, everything was in bloom. We liked Fira better than Oia, had more of a traditional city vibe, good restaurants and better prices in shops and accommodating shopkeepers.
If you stay anywhere else on Santorini, you will really have missed out. Even the cats were welcoming, specially Cici.