Dimitris's place is located a short walk from the center of Chora, where you can find everything you need on the island. The apartment is clean, neat, air-conditioned, and has everything you need for a short or long stay. There is view of the Castle from the balcony. My boyfriend and I stayed a week, and the room was cleaned twice while we were there, which was an unexpected but helpful occurrence.
Dimitris himself is real star of this location, however. He not only arranged taxis and car rentals for us, but also showed us the local restaurants, gave us tips on beaches, and introduced us to local foods. His mom would stop by the apartment to give us small treats (or, in our case, Easter-specific meals!), or to sell her homemade marmalade (worth it! Try it with yogurt). Dimitris also offers Thai massages at a discounted rate to guests, with all proceeds going to charity.
In short, we felt welcomed and supported throughout our stay, and will definitely be staying with Dimitris whenever we return to Astypalaia. We strongly recommend Dimitris's place!