It was my first time in Athens and I think Konstantinos' place was perfectly located for someone like me who enjoys the sights and sounds of a new city. The apartment is very spacious, just the bathroom is very small like most European places but perfect for my friend and I. We were back and forth between places in Greece so it was great to be able to do a few loads of laundry at the apartment while we were there.
We were walking distance to all the hot spots of Athens including the infamous Acropolis. We used the metro from the airport to the apartment (1hr trip) and the walk is a mere 5 minutes to the apartment from there. All your meals are literally around the corner if you are feeling lazy and we felt safe and comfortable during our stay. If you are eating at the apartment, be on the balcony as the view is wonderful.
I would definitely stay here again!