We were a group of three friends who stayed at Vivi&Andreas' place for 4 nights in late June. Everything was great - the location (literally 2 min from the main square in Thira), the apartment (very spacious and clean), the communication with the host (who offered us great tips and suggestions and also helped us with renting a car from the office downstairs) and everything else.
Would definitely recommend Vivi&Andreas' place and I hope I will come back next summer!