Location is excellent. Right by a metro station (perfect for getting to and from the airport) and walking distance to many sites such as the Monastiraki, the Acropolis, Syntagma Square and many, many more.
Amenities are very good and include a gym, rooftop (Acropolis-view) diningnand free WiFi.
The only negative mark I'd give the Brown Acropol are towards its staff. They come across snooty and only do the bare minimum when it comes to customer service. Their bellboy was rude. I stayed there a week for business and didn't see a single one of them smile during my entire stay. However, their cleaning staff were helpful and friendly.
Probably would not stay at the Brown Acropol again as there were several other options in the area.