Overall was all good. Everything is super close in walking distance: sightseeing stuff, metro, good restaurants and bars. Communication with Konstantinos is very easy. Everything was clean. Therefore price/value is ok.
Nevertheless, here some details to consider for future guests: on weekend nights its very loud, because the studio is in one of the busiest nightlife streets. Even though the room has no window towards the street (actually no window at all!) the whole building is buzzing from the music.
This place is no appartament, it is a physiotherapy studio and you sleep in the "office". That felt a bit weird, also because we never knew if on the weekdays stuff and clients are gonna show up in the morning... but we were all the time on our own, we have never seen anyone.