We had a really great time in Athens! It was our first time and we were very happy to have such luck with our accommodation.
Manos is a great, kind and helpful host (Lia too for sure, however we just met Manos :-) ). If there is any problem occuring you can contact them right away since they live just next door (but there's also a phone in the appartment to leave a short text message).
The appartment had everything we needed for our short stay in the beautiful city. The location is also very (!) nice, lots of points of interests are within walking distance. For a longer stay in Athens it might be useful to have some kind of cooking facility. However there are many nice places to eat nearby.
Here and there we had some problems connecting to the wireless LAN (despite there are two possible networks), but being a little patient it always worked somehow.
One other thing to mention (mainly important for people with a more easy sleep) is, that the house is a little clairaudient. I woke up a few times in the first night, caused by the noise (or rather sound) of several pigeons not wanting to stop cooing around in the court. :-) I gladly had earplugs with me, so I could sleep afterwards....
We definitely recommend the appartment of Lia & Manos for a stay in Athens. We are happy to come back some time in the future!