We've stayed in lots of places in and around Athens while traveling with our two children, from Plaka hotels to Pagrati apartments. It's rare to find the space and comfort of a real apartment in the center of all of the action. I think this location is the best possible: the Akropoli Metro stop, the Acropolis Museum, the Plaka, Monastriaki, it's all there.
The apartment is extremely well appointed while still being minimal. The kitchen is the best I've seen in Greece. Stainless steel sink, new appliances, plenty of dishware and cooking utensils, which are all tempting, but Athenian restaurants are even more tempting so we didn't get much cook time during our short stay.
Both bedrooms were very comfortable, and having two teenagers enjoying a shared room is saying a lot about how comfortable it was.
Stella communicated really clearly and was helpful throughout. We'll be staying here again, and I recommend that you do too!