The apartment is wonderful, beautifully appointed, and easily accessible. The roof terrace was a great place for breakfast, which we bought at Lulu's deli every morning. The view of the roof-scape, and the acropolis is superb and most days someone played a clarinet nearby.
The area is full of cafes and shops aimed at the tourist market, and Syntagma Square and Monastiraki are about 20 minutes walk away. The acropolis walk-way, the Acropolis museum and the metro is 5 minutes away.
There is very little motor traffic in the area, it's mainly pedestrianised. It was a bit noisy in the evenings as people went out to eat, or buy ice-creams at the store under the apartment (really good), but the double glazing effectively keeps the sound out.
I would recommend this apartment. One of our party is not very mobile, but he could use the lift to the apartment, and the streets were pretty safe with so few cars. He even made it onto the roof.