This apartment is great, mostly because it could be used for a variety of purposes or travelers. In our case, we had a couple and two friends, so the three bedrooms and bathrooms were perfect for our needs. There was space to sit outside, the living room was stylish and, most important, the location is ideal. Right at the intersection of Monastiraki and Plaka, access to transportation, shopping, and the Acropolis area is within easy walking distance.
Our only very slight issues - that we felt are worth mentioning but are in no way dealbreakers - were a homeless man sleeping just outside the apartment building entrance both nights we stayed. He posed no threat or harm, but it does seem worth mentioning. Additionally, the second bedroom had a slightly bothersome humming noise. For the light sleepers out there, this room would likely not be appropriate.
Those small issues aside, we had great interactions with Alexi and his cousin, they were flexible with our arrival, and the apartment itself could not have suited our needs any better. Five stars.