It was a nice experience! George's house is clean and comfortable, just look as same as the photos described. You can have a warm apartment with all you need inside. You can buy material from market and cook in the house or order food from restaurant in Thira(they have free delivery service) if you dunt wanna go out at night.
It's location is nice too. Though it's not in the city centre, it is already very convenient with regards to its price. Thira is in walking distance of 15-20 mins, you can have shopping centre, restaurants, markets, souvenir shops there. The nearest mini market is just 5-10 mins walking. There is also a bus stop where you can take bus to Oia(where you can enjoy the wonderful sunset) near the apartment.
Moreover, George and his wife are nice! They are responsive and helpful. You can get information about Santorini from them! One point to remind is that, they also provide pick up service from and to airport. As the public transport system in Santorini is not really convenient, so you may consider their service. They charge similar price as taxi but they have a mini van where you can have enough space for your luggage, especially you come as a group of 4.
The only thing we have comment on is that the house is quite cold during night, maybe that's because we visit Santorini in mid Mar. George is nice, he provided us a heater when knowing our situation. Anw, I think this would be a problem if you visit Santorini during Summer, the temperature in the cave house will be nice I think.