The location of the flat is perfect, close to all the main attractions so if you go to Athens for a short stay without much expectations is good.
For a long stay or if you are looking for comfort I would say there are other options.
The flat have 2 boilers for the hot water, one for the bathroom, one for the kitchen and you need to switch them on for 30 min if you wanna have hot water. In the instructions about the boiler it says to switch it off while taking the shower so if you like long hot shower especially in winter (I visit in January) is not ideal as the hot water might run out.
The Wi-Fi worked the first day but then it stopped working, I switched the router on and off several times as instructed in the leaflet left in the flat but nothing, so I then used my personal Internet allowance.
The flat is on the ground floor with the windows next to the street, but even though is near the main attractions is not noisy at night. Obviously I don't know how busy it is during summer time without covid restrictions, but it looks a quiet alleyways.
Overall the flat is in a good location, good quality/price but some bits can improve.