We stayed in Semeli cave house for 6 days with 2 children ( age 9 - 11 ).
We had a very nice time in Santorini and in the Semeli cave house.
The house is located in a less touristic part of the island but it still only takes you 10 minutes to the nearest beaches or 15 minutes to Fira (capital). The closest village ( Pyrgos ) is only 2 minutes away where you have a very good bakery and where you can find a mini market and restaurants.
You will need to rent a car or quad to drive around the island. From the terrace of the house (with jacuzzi) you have a nice view over the sea and on the upper sun terrace you have he sun till diner time.
The two hosts ( Maria - Marilou ) do make a difference ! They help to carry your bags, give you all the information you need about the island and always respond quickly to a text message question.
Ok, you need to go up and down some stairs to go from the parking to the house but hey want do you want, it's Santorini :-)
Wat can be improved is the shower : bit cold - comparable to the Aegean sea.
We can certainly recommend the property for those who do not want to be in the crowdiness of Fira or Oia.
At last : Have dinner at Taverna Metazu Mas Ouzepi. You will need reservation but it is worth the while !