We had a great time at Efthimis flat and in Athens! The flat was centrally located, which enabled us to spent our time on foot without using metro (although the flat was very close to Thissio metro station). Everything was in walking distance, area was safe.
The flat itself was nice, equiped traditionaly (with everything you need for spending several days in Athens) and had a nice green terrace with Acropolis view.
Efthimis was very nice and helped us with valuable local suggestions, such as bars, local places etc.
Only the thing which could be improved, was relatively small bed :)