Our stay at Spiros and Electra's place has been very good. We have been in Athens 5 days with our little daughter (4 months old) and the space in the apartment was just perfect for our little family, it is perfect for a couple. Very clean and the communication with Spiros has just been great. He answered always very quickly to our questions :) The view from the balcony is beautiful, although we could not enjoy it because of the weather. It is close to the main sight seeings (everything about 15-20 minutes by feed) Acropolis, Zeus temple, Stadion, Plaka neighbourhood. In fact we got the 5 days metro ticket and didn't use it (only two days). Anyway, if you plan to travel with a small child, I would recommend to stay in Monastiraki/ Plaka or Psyrri, as it is much more central and you may need to go home during the day (one or two times) for your baby to chill and take a rest. If you don't need it, then it is perfect to stay there also with a baby.
All in all I would definitely recommend it! :) Efharisto Spiros!! :)