Ouiliams place was amazing.
Pretty much central to all the best places to visit and explore. Everything is in walking distance.
The place, itself, is probably one of the best I've been to. It was clean, very spacious, and its nestled in the back of the busy street, so you get no noise when it's time to unwind.
Communication with Ouiliam (and Stella) was great. They made sure to let me know how to get into the place.
I can honestly say, there is nothing to complain about this place. If you ever visit Athens, definitely book this place :)