This apartment was perfect for me as a solo traveler. I was able to walk everywhere because it was so centrally located. It is also literally steps away from a Metro station (which I didn't personally use because I prefer to walk when I can) and steps from Monastiraki Square.
The neighborhood of Psyiri is quite lively with many local restaurants and bars. Because it is right by many bars and also Monastiraki Square, it can be quite loud. It wasn't a problem for me, but if you're a light sleeper maybe bring some ear buds.
The apartment was also extremely easy to check into, super clean, and provided a converter for the outlets, which I really appreciated because I forgot mine.
The hosts are also friendly in all communication and thorough in their responses. I extended my stay by a fee days and they were very accommodating.
I had a great stay here and will definitely come back next time I'm in Athens.