We really enjoyed our shorts hilly walks to the nearby center, and the neighborhood itself was beautiful with plenty of nature all around. As other reviewers noted, a lot of politicians including the PM live in the area so there is a police presence on some of the corners/blocks (I had wondered why before reading the reviews).
We walked up to Lycabettus Hill for the gorgeous views as suggested (there is a cafe near the top too). The wifi was fast and the AC and washer worked well, and the hosts were very responsive and friendly when we had a few questions. We only took the Metro once (Evangellismos) and it was about a 15 minute walk, not bad at all.
One thing the building needs to fix: Someone sometimes locks the outside door from the inside making your key necessary to get out. Could be dangerous in a fire situation and you can't find/get your key? So when you are checking out, make sure you ensure the door is unlocked first.