I was recently in Berlin for two weeks and stayed at the Movenpick Hotel near Potsdamerplatz. The hotel itself is right off of Anhalter S‐Bahn station.
The front desk team were phenomenal, especially a gentleman called Takimann (I know I just butchered his name - please forgive me for doing it). There wasn't anything we asked for without them getting it in two or three mins. Kudos to the Movenpick management for finding such amazing individuals.
The room was also nice, but needs a bit of updating, especially the shower. The shower head didn't remain in place and kept sliding down the pole. There were also a couple of towel hangers that fell off (before we got there).
Overall, if I'm ever back in Berlin, Movenpick will be my first choice of hotel to stay at.