The apartment is perfect for a couple. It was clean and organized, and the location was fantastic! The place is walking distance from all the great attractions (acropolis, parliament building, national garden, etc...), tons of fun shops and delicious restaurants.
Tong was very responsive, and met us on the street at check-in. Our flight out of Athens wasn't until midnight, and since no one was checking in that day, Tong let us stay after check out. That way, we didn't have to carry around our luggage every where, which was a life saver.
The only thing negative about the apartment, which is relatively minor overall, was the hot water. You need to "turn on" the water heater at least 30+ minute before you shower, and even after that, the hot water only lasts for a few minutes. We ended up taking cold showers each day... However, based on the location, cleanliness, responsiveness, and price, I would book this apartment again if we ever come back.