The place is perfect, clean, spacious, great hosts, easy check in, but the highlight...
The location.
The Acropolis becomes incredibly crowded within an hour or so of opening, thanks to the proximity of the flat, you can grab a bite and get to the gate within minutes, meaning you get those rare unobstructed views.
It's easy walking from the metro, from Syntagma, from Plaka, and, provided your relatively fit, from the more trendy and arguably less touristic areas to the west of the Acropolis.
I can only say thanks and thanks again,