We enjoyed our stay at Elsa's place. We had a very good time in Mykonos and it was also due to Elsa's help, tips and tricks.
The place was really clean, the kitchen well equipped and the view through the little bedroom window was really nice. Good location on the western side of the island, not more than 20 minutes (by car) from any beach, close to a big supermarket and Chora.
So, yeah, i would definitely recommend Kosta's place and hope to return in the near future.