We only spent one night at Kostas's, we were welcomed by his mother who showed us around and was helpful with whatever we needed (there was one problem with the apartment but immediately after we let them know, they came and fixed it, additionally bringing baked goods) :D
The place is not too big (as seen on the photos), but the bed is comfy, it is silent and very close to the sea/restaurants and the Old Port :) Recommended!