We stayed in the apt on Appolonos,5 for 5 days in April 2013.
The location is brilliant - just a short walk (4-5min=300-500m) from Syntagma metro station, a bit longer but pleasant - from Monastiraki metro station and 25min on foot to Akropolis. The location is beneficial also because it's just in the middle of the area with different places of interest - ancient sites, Archeological Museum, park, Likavitos, Filopapou, Ermou street with shops. I went on foot nearly everywhere except the airport.
At the and of the Voulis streen nearby there is a great cafe - Paradosiako (sorry, if spelled wrong) - good food for decent money - 25EUR for two made us more than full :). And on Syntagma near McDonalsds there is the cheapest frozen yougurt in Athens - 1EUR + 0.5 for topping.
Another street nearby - Petraki - has a good 8am to 8pm super market.

Finally, we were content with our stay.

Liked:
=Location&location&location
=The host let us in quite early on Saturday which was really very pleasant after the night flight - we slept half a day :). Great thanks for that, really.
=Big double bed in the main bedroom (i.e. 1.8m wide), airy bedroom
=All necessary equipment in the apt (refrigerator, toaster, washing mashine, ironing board, drying rack, iron, small oven, 3iron stove).
=Second bedroom actually contains an IKEA 1.4m double bed which is quite okay for a single person, one or two children or a couple if they are not giants each :)
=It was not hot so we couldn't comment on air conditioning but there was air conditioner and ventilator in the bedroom.
=Enough towels, blankets, pillows and other linen... Just in case you need it.
=Hot water is available all the time. The sanitary was really clean - I do value that.
=The entrance to the house feels safe. I am not late wanderer but I felt generally calm walking in and out in the evening.

Disliked:
=There is a computer in the living room, but don't rely on it - it's really slow.
=No electrical kettle/boiler - I need time to get used to it - all the matter is that I was surprized that fully equiped kitchen doesn't include the one :)
=No hairdryer.