I had a lovely stay at Alexandra's place and would absolutely come back! The location was just about perfect - incredibly close to Voulisma Beach and across the street from several tasty restaurants, but still isolated enough that it was a restful place to stay and listen to the waves and crickets at night.
Several of the supermarkets in Istró aren't open yet, so bring groceries with you if you're planning on staying in for any meals. The only issues I had at Alexandra's were the washing machine (it doesn't connect easily to the power and the water tube without blocking off the bathroom door, and then it didn't drain properly) and the toilet occasionally didn't seem to be filling properly. I was there for such a short time that I didn't ask for either thing to be fixed; Alexandra was incredibly responsive and I'm sure if I had brought them up, they would've been fixed as quickly as possible.
Overall, absolutely enjoyed my stay here and highly recommend it to anyone looking for some peace and rest :) Thanks, Alexandra!