Four friends, my girlfriend and I stayed at the Horizon House for about a week while in Santorini for a wedding and we were thrilled with the experience. Communication with Nikos and those who work with him was perfect. The views from the house were incredible and there was plenty of room for all 6 of us to fit comfortably.
Emporio is a bit quieter than other parts of Santorini but there was a bus stop a very short walk from the house where we could catch rides to Thera, the capital, and to the beaches in Perissa. All in all, it was a wonderful experience and I would strongly recommend the house to anyone visiting Santorini.