Casa Sofia is absolutely beautiful. If you are looking for an 'authentic' Santorini cave house experience, this is perfect. The view over the ocean is stunning (especially at dusk) and you are right in the middle of a very residential feeling area, yet within five minutes walking from the main shopping & restaurant street.
Major note - there are several hundred stairs you will have to descend every time you walk down to the house, or up to town. In summer this is an extremely hot walk - however its also all part of the experience.
Also - several of the photos in this listing are not actually of this house. The kitchenette down some stairs, and also the bedroom with stairs shown to the side are not in this house.
I only saw Maria once during my stay, but she was very lovely and offered me anything I needed. The two men who help her are amazing (I definitely recommend the port / airport transfer - you would struggle to find the house on your own, especially trying to carry luggage down!) but they are incredible and show you to the house and carry all of your bags.
Wifi and air con in the house are both good. The bathroom is outside, however only a few steps from the front door. Was not an issue to us.
Overall we had a very wonderful experience at this beautiful house, and would definitely recommend to others.