We had a wonderful stay! Panos' mother was an excellent host and made us feel welcome and always willing to help us. The continental breakfast on the terrace was a nice touch. Also you can go on the roof to view the Oia sunset.
The building is old but kept clean and has a charm to it. Note that there is no AC but there was usually a cooler breeze at night, at least in mid-July, so we kept the windows open. There a lot of dogs in Oia that sometimes bark a lot at night, but nothing earplugs couldn't fix.
Overall the stay was highly recommendable and a great location.