We spent 5 amazing day at Rena's cave house and already planning on going back later this year. Communication with Rena was top noch. She also arranged our transferes to/from the airport and had a porter bring our bags to/from the cave. One thing to note is that there are a lot or steep steps (100+) leading to the cave, so it is highly adviced to bring small suitcases. We were on the road for 6 days prior to arriving in Oia, so had two large suitcases with us and the porter had a very difficult time carrying them.
The cave its self was as pictured and then some! Clean, comfortable and had everything we needed. AC was a big plus! Rena even provided coffee, water, wine and home made bread upon our arrival. That was very nice of her. A nice lady came to clean the house daily and provided us with fresh towels. The jacuzzi is also as pictured was very cool to use after we figured out all the light switches. Views from the cave were spectacular and there are two levels of private outdoor sitting areas from where you can enjoy them. The outdoor areas is also where you can get good Wi-Fi. Since the router is not directly in the cave, the signal inside is very weak.
For animal lovers there is also a bonus! About 8 cats and some dogs live near the area, who would appriciate your food leftovers. Nearby supermarkets also sell pet food! :)
Overall it was a fantastic experience and Rena is an amazing host.