I wanted that to be an entirely positive review because Anna and Stathis seemed like genuinely nice people and the communication with them was perfect.
However, there are several things you need to consider before booking this apartment. It is also important to note that our group consisted of four people and not everything I write would be relevant if you are booking the apartment as a couple.
The Metaxourgeio area is quite rough. We saw people shooting, smoking from glass pipes and snorting meth straight from the stone stairs in the very neighbouring streets of the apartment. All on our first day there. Very common to see passed out people. Not that unfamiliar with that where we come from, but was far from a pleasant experience, to put it lightly. Police seems to be trying to change that, as we saw two police actions in three days. We also heard the neighbourhood is getting better, and we visited a very really nice gallery there, so hopefully when you read this review things would have already changed for good. Still, as of the date of writing this, I would not recommend this area compared to other options, especially to people with kids, people that look more touristy, and people alone at night. A great thing about the neighbourhood is that it is incredibly easy to get out of it - either with the metro or by walking, and it is relatively close to most major highlights.
The apartment itself is nice and cosy and would be perfect if you visit as a couple, but we were a group of four. The listing said there are two double beds, but the second was a wacky self-disassembling does-what-wants half-sized convertible sofa that would be a hell to sleep on even for a single person, not to mention two. It was a huge pain in the back to sleep on it - a truly uncomfortable bed. And then we woke up partially on the floor. Fix that and maybe add a washing machine for longer stays and you will have an excellent apartment, even for groups of 3-4 people.
The balcony is magical and deserves a special shout out.