We stayed in the apartment for 11 nights, just after the local lockdown was lifted. Firstly, the location of this place is absolutely amazing if you've not spent any time in Athens before (which we hadn't). We only took public transport once to go to the beach, but other than that everything was there right on the doorstep. Not only that, it was really quiet. I don't know what it would be like in the height of the tourist season, but at night all you could hear was the occasional street performer in the distance.
Dimitris was always available to help out if any issues arose (there were one or two), so can't fault the communication.
The apartment itself feels a little tired and needs a bit of TLC (I rated this 4 stars, but could easily be a 5 star place if a little more love was put into fixing things up a little). We split our time between remote working and tourism, and the Wifi in the apartment was perfect, as were the cooking facilities (minus a few 'essentials' such as sharp knives and tea towels) - although all of the restaurants nearby meant we didn't quite eat in as often as I'd originally planned.
We were there as a couple, and the apartment was a perfect size for two people. It's listed as a two bedroom place which is a bit of a stretch as the second 'bedroom' is a mezzanine level within the first bedroom. So unless you're happy to be on top of each other (literally), then it may not suit multiple couples. There was a sofabed in the living room area, but you do need to pass through the bedroom to reach the bathroom from there. There's an outdoor area which also doubles up as the entrance to the apartment complex so isn't really that private, but still nice to have.
So if you're after somewhere right in the centre of Athens, and want something a little more authentic rather than stay in one of the many indistinguishable modern apartments that are available, then I'd recommend this place.