We stayed in both apartments. They are stylishly designed and have a lot of cool features. Tons of books and pictures. The kitchens have everything the you need plus some basics like oil and some spices. The rooftop terrace was the highlight for our group. We enjoyed our time up there and even ordered from the restaurant downstairs. Which I recommend for their tasty food but also because they don't pester you like so many other restaurants in the touristy area of Athens.
There is a whole Mary Poppins area near the apartment, complete with umbrellas hanging so naturally there are always people snapping photos. It is also only a block or two from the flea market. Our group highly recommends starting your morning at, The Happy Blender for a juice or smoothie to help combat a late night out :)
The host gave great recommendations and even gives you a map with everything written down. I would recommend staying here to anyone visiting Athens.