Katarina's place is in a fantastic location and was a comfortable base. There were a few minor issues like missing plugs from the kitchen and bathroom, doors being difficult to close (and very squeaky) but the apartment is professionally managed so very responsive to issues (they even had a stash of plugs when we asked for one). There are great restaurants just downstairs and walking distance to Mall of Berlin, other shopping districts and tourist attractions like Brandenburger Tör.