I can honestly recommend this apartment.
1) Nestor - he was friendly, helpful and available at every time! Best host.
2) Apartment - huge! We were in shock! It was very clean and great for us as a group of friends - separate bedrooms and big living room. I'm sure it would be also great for families. It has everything we needed (kitchen stuff etc). There were instructions how to use air condition and hot water and we had no problem using it.
3) Location - near to subway station and train station, but we decided to walk mostly. Akropol is around 20-25 minutes by foot, Archeologic Museum is less than 10 minutes by foot. The neibourhood was crowdy, but nobody bothered us, we didn't feel uncomfortable.
4) Keys - you can get keys without bothering the host. For example, our plane had 2 hours of delay and we arrived to Athens at 2 AM. There was no problem with entering to the apartment.
And the price was very good:)