Beautiful apartment, extremely spacious, excellent location with plenty of shops and restaurants outside - walking about 7 minutes from the Syntagma station and 20 minutes to the Parthenon.
Good communication, they let us drop our luggage off at their office a few hours before check in (about 30 minute walk from the apartment).
One thing to be aware of - you have to turn the water heater on for the shower 30 minutes prior to using, and then it only stays warm for 6 minutes (we timed). Hopefully it was just a fluke with our stay, but it made it a bit difficult for 2 people.
Overall very nice place!