We absolutely loved our stay at Armeni beach.
Christina (Nicoletta's daughter) tended to all of our requests and helped us to arrange various transfers, excursions and general assistance within 30 seconds of a text message sent to her. She even let us check out at 18:00, as there were no guests arriving on our check out date - our flight left at 21:00, which meant we really had a full final day to enjoy at leisure.
The house itself is as per the photos. It has little pearls, such as bath and swimming towels, breakfast nibbles and ground coffee for use in the coffee machine. There is even a cleaning lady that comes by every second day. Certainly above and beyond your typical airbnb stay.
Its good value for what is not a cheap holiday destination anymore - we were a group of 6 adults and managed quite comfortably. The stay for the 6 of us cost in many instances less than what a villa for 2 up in town would cost, for something a lot less quaint and unique than what we enjoyed in Armeni.
The only negative, if one can call it that, is indeed the steps one has to climb to get to the top of Oia. My wife is pregnant and could not manage to get herself up more than once a day. It really is quite challenging and not to be underestimated if one travels with small children, elderly people or people with medical conditions. It is of course exasperated by the intense heat one has to endure during the glorious summer days of Greece. That being said, if you are reasonably fit and know what you are getting yourself into, I would certainly recommend the spot. It provides a calm retreat from the bustle of town and you do sometimes forget in an oasis of bliss, where you can jump straight into the Agean after your morning coffee...
In a nutshell - We loved it and hope you will too.