We had a very nice time on Milos, it is beautiful island with lots of great things to do for a week easily. Christos' place has a great location right over the sea, perfect for relaxing and enjoying the nearby beaches. The kitchen is well-equipped, there is a nice balcony suitable for two and good 1,40m bed.
Unfortunately, our experience with the apartment was a bit mixed, and not worth the 150€ per night. We felt that the photos and the description of the apartment are not exactly matched by reality - our impression was that the apartment is fairly basic and some vintage furniture plus Ikea all over the place. In particular, the bathroom turned out to be disappointing, and we were quite happy to be back home and have a decent shower.
Christos was a very friendly and helpful host, collecting us at the ferry port, arranging car rental and showing us around the house - also his recommendations were excellent, and we could well avoid the island's tourist traps.