If you are looking for a nice apartment for 2-3 people in a quiet residential neighborhood with lots of great (authentic/non-tourist trap!!) greek restaurants around and good bus connections to the center of Athens - then go for this apartment!
We stayed at Kosta's apartment for four nights and we can only recommend it. It's clean and has everything you need. There are several bus stops in 2 to 5min walking distance around the apartment and the bus connections are great, frequent and fast. It won't take you more than 15-20 minutes to get to the centre. Kostas replied to all our messages super fast and his parents even made the effort to receive us for check-in and were incredibly kind. Thank you Kostas for the nice stay!