I stayed with 2 other friends at Eleftheria's place. The apartment is centrally located in Fira, close to the shops, restaurants and the bus station. Elle was a great host and arranged taxi transfers (€10pp) from the airport in advance. The apartment was clean, had contemporary decor and the rooms were spacious. AC in all rooms was a welcome relief in the hot weather. Note the doors to all rooms, including the bathroom, have large panels of frosted glass.
If you're a light sleeper, do not choose the room with the balcony as some noise/music does filter through. On the whole, the apartment is very roomy, comfortable and we would thoroughly recommend it.