The apartment is really nice, exactly as decribed and fully equipped with everything one needs! It's located in a quiet neighborhood, but still close to the ICC/Messe and public transportation, which was perfect for me.
There was a minor issue about coordinating my arrival (due to a family member being sick, so totally understandable), but Britta and her husband were always very helpful, flexible, courteous and responsive, both prior to my stay and when I got to Berlin. I would certainly stay there again and recommend the apartment to everyone!