Honestly, apartments are gorgeous: high ceilings, marble floors, wooden doors, lots of daylight, huge terrace with spectacular view of the Parthenon. It has all the equipment needed so we spent a nice week there.
Despite the fact that location is quite safe, and you have a pocket-park in front of the house, be prepared to the fact that there are not so much good cafés and bars in metaxourgeio. So, if you want to hangout, you will have to spend 5-10 min to reach keramikos.
I think this apt would be great for long-term rental, the only problem was with the wifi: it was not very fast and sometimes we had to restart the router to make it work again. But I do believe that Maria will solve this problem :)
Btw, Maria is a perfect host: helpful and welcoming. It was a pleasure to communicate with her.