Stayed here for a couple weeks and it worked out great. I'd definitely stay here in the future. Sokol was quick to respond to messages and kind enough to check in and see how I was doing periodically.
The unit is well-stocked, but definitely compact. If you're expecting to do a lot of cooking it might be annoying with the bed so close.
It's in a very convenient location. A short walk to Gazi, Psyrri, the central market. Close to the Acropolis and surrounding neighborhoods, but outside of the most crazy touristy spots. The immediate area around the apartment has graffiti and is a bit dilapidated, but I didn't have any issues or feel unsafe.
The internet speed was the only thing I found lacking. During my stay it averaged around 1.5 megabit down and 0.5 megabit up. To be fair, I didn't need it much so I didn't complain to Sokol. Maybe they could have improved it.