Kostis' hospitality was above and beyond. He responded very quickly (even when I didn't) and really took care of me and my friends. His recommendations for where to eat and the best ways to deal with the logistics of touring were very delicious and helpful, respectively. Of all the places I stayed in Greece, Kostis' had the best amenities. The upright shower was a godsend after a week's travel and having two bathrooms for the four of us definitely made a difference.
The only complaint I have is that the wifi was frustratingly slow. Despite some mattress covers, the beds are hard, which two of us thought was completely comfortable, but my other two friends who have some back problems both had a tough time with.
The rooftop view was even better than the pictures indicated.