Nikos's place was clean and comfortable-- a great value for the money. Nikos also offered many amenities like bottled water in the fridge and a washing machine, which were nice. Nikos was also kind enough to meet us much later than expected due to a delay we hit earlier in our trip.
The apartment is a little bit farther from the Acropolis and other destinations than some other places, but everything is still easily reachable from the subway. The apartment can be a bit noisy. However, I'm not sure if this is a general feature of Athens, or specific to this apartment.
Overall, we were very satisfied.