We had an overall good stay at the appartment and can recommend it. Plaka is one of the most beautiful dirstricts in Athens and the location of the apartment is just perfect. The roof terrace is also genius.
However, there were a few things which we didn't like as well:
1) There is a strong smell in the flat which we couldn't get used to.
2) It can be very noisy at night, especially as the walls are very thin.
3) There is no daylight in the apartment as it is a basement flat.
If you disregard these things, it was a nice stay. Pan was a great host and always answered very quickly.