We really enjoyed our stay in Dimi's apartment. The flat wasn't big but it was very originally furnitured and fully equipped, and clean as well. Big advantage of this apartement is a large terrace with a view. AC also worked well. Cetre of Athens is easily reachable on foot or by metro. You should also visit Filopappos Hill which is located about 10 mins from that place and which guarantee best views in Athens.