The cave house is beautiful and stylish, in one of the best spots within Oia. The view from the porch (just up the stairs from the house entrance which sits down in an area shared with a couple/few other houses) of the sunset (one of the best aspects of Oia) was phenomenal, ignoring the torn down building just in front. Giannis was very courteous and accommodating, even making reservations for us and providing a place to leave baggage after checkout on the final day--easing our travel load. He met us at the Oia bus station and navigated us through the town alleyways.
The interior is immaculate and was well stocked with toiletries and food. We didn't eat much there, since the food at the local restaurants was so great, but snacks in the morning allowed us to jet out early and modulate hunger. Find something to put in front of the bright exit sign over the door at night and be sure to place a towel down on the bathroom floor after showering since a good bit of water splashes out onto the slippery floor.
Well recommended. Oia is a very special place and this is a wonderful place to stay to experience it.