We stayed here in early March, so this review reflects the winter time/off season. On the positive side, not a single tourist went onto the property to take photos. The view is absolutely amazing, the hosts were super attentive, we appreciate that they helped with our bags for the 10 minute walk from our car to the place, and it was an authentic cave. It was a unique place to stay.
On the less positive side, it is hard to heat up the place and hard to cook. There are 2 electric heaters, but with the high ceilings it is hard to feel the heat. The kitchen is not really made for cooks. The cooktop is the same unit as the oven, and you can only use one part at a time. There is no microwave. There are enough dishes to eat and cook with. If you only plan to have breakfast at the place, then this probably won't be an issue for you. The big challenge was that our electricity cut off at least 10 times over the 2 days we stayed there. We couldn't have the heaters on when all of the lights were on, and certainly not while cooking. This was very frustrating. And the only thing we could do is turn off every light that we didn't absolutely need. The hosts explained that it is an old power grid. We would suggest staying here when it is not too cold and not too hot.
In the end, being in Oia was an absolutely unique experience and this home is truly unique.