Hotel / B&B recommendation (Berlin)

Hi there, I'm sometimes in Berlin, but now I have been asked to recommend a hotel and I really don't know much about hotels in Berlin. So, I need help.

My friends are looking for a nice hotel away from the tourist areas.
Something in a more residential district, less touristy, more local. Somewhere where they might enjoy going out to eat in the evenings, if they've been seeing the sites in the centre all day. I would imagine somewhere like Prenzlauer Berg, Friedrichshain, Kreuzberg, Schöneberg.

Most hotels seem to be more in Mitte, and then in the areas mentioned there doens't seem to be much choice. My friends are happy to pay for something nice.

Thanks for any suggestions.