The location of this apartment was great! You really are in the middle of everything and you can walk to all those interesting sights. It is a bit smaller than I thought but worked perfectly for our family ( 2 adults and kids 9&11). It was also a bit surprise the apartment was halfway under the ground - but it was probably the reason it also kept pretty cool although it was really hot out! And the aircondition worked while in the apartment.
We only had one set of keys and a electricity card was also binded with keys - in the morning when one of us went out to get some breakfast had to run around with the key (you needed a key to get out from the door out) and wait in the darkness for a while as he had gone opened the door. But it was ok!
I would book this apartment again if visiting Athens!