We stayed at Blackcoast for 5 nights and it was a great stay. The place is lovely; nice room with great terrace, lovely pool, well equipped kitchenette. The host was amazing, very sweet and welcoming and eager to help.
The place is nice and quiet, 2 mins away by quad (around 10 mins walk) from Perissa beach and loads of restaurants. About 20 min drive from Thera.
Despite the distance from the main cities, I would highly recommend as it is a great getaway from the more hectic cities.