We had a great stay and highly recommend the Myst Boutique. The staff (and owner, whom we met) were incredibly helpful and friendly. The hotel is spotless and in excellent condition. The pool is beautiful. The key is making sure you understand the location. It is just outside the center of Oia and does not overlook the Caldera, and the rates reflect that. The good news is you are away from all the crowds and noise, and the hotel staff is great about arranging rides and pickups, which can get you to Oia in five minutes. Definitely consider the Myst if you are planning a Santorini visit.