Happy with my month stay here. Important things -- internet/wi-fi was reliable (sign on to both networks provided by the host; the main one goes down on occasion, but the other picks up the slack), air conditioning works, shower is good. Not far from Psyrri, so lots of outdoor eating/drinking options to choose from. The hosts are very responsive -- I had a problem with the bathroom about 2.5 weeks in, and it was fixed by the next day. Was extremely happy with that, and I could tell that they really cared about my having a good stay. The hosts provided a cleaning service every week, which was great -- when you're staying for a few weeks, it's really nice to get a refresh on sheets and towels. The host also helped me order a cab to the airport -- a nice gesture on my way out the door.
The downsides of the place are already in the other reviews. There is a lot of street noise at night (esp. on Friday and Saturday, but this is because you're near Psyrri). Also, as with many places in Europe, there's one A/C unit -- it works well, but to cool the apartment, you need to leave all the doors open, so there isn't a ton of privacy if you have multiple people staying. Neither were dealbreakers for me -- I don't think there's such a thing as a perfect AirBNB, but these downsides aren't so bad.