We have been to Santorini during our honeymoon. Giannis place is amazing!!! The view from his private terrace is breathtaking. The location of the cave house is really good. Local supermarkets are everyhwhere near and it is located near Oia castle (known for its beautiful sunset view).
We haven't met Giannis but he was always willing to help over the phone. We have met his team; Dimitris and Dana. They are very kind and helpful. They have arranged everything we asked for.
Bottom line, Giannis place is what you are looking for in Santorini!!