Being based in Berlin I have never stayed in any of the hotels here. What I can say is that I would decide about the location first and then choose the hotel. Choosing a location I would look at the part of town (e.g. Gendarmenmarkt, Potsdamer Platz, Brandenburger Tor, Zoo, Alexanderplatz) as well as the immediate "neighborhood".

Maybe try something smaller, more boutique:
http://www.das-stue.com/
http://www.hotelsteinplatz.com/

Stue is very centrally located between eat and west, but the immediate surroundings don’t offer much. Steinplatz is in the heart of old West Berlin near Zoo station.