I stayed in the Großer Kurfürst Living Hotel in Berlin from 1/9/21 to 1/12/21 - three months, and it was an excellent stay. The hotel has a number of apartments as well as regular rooms. The apartment (33sqm) was perfect for one person (and would have been ok for two people also, as there were twin beds and enough space). It comprised of a small kitchen, table and chairs, a bathroom and a large room with twin beds at one end and a sofa, easy chair, and an office desk at the other end.
It was quiet and comfortable with some restaurants and a supermarket close by, and a U2 U-Bahn station, Markisches Museum, just outside the door, although I mostly used a bike to get around Berlin and the hotel stored it safely at nighttime in the luggage room.
The small kitchen was perfect for preparation of light meals, the Wifi was fast, the bed was comfortable, and a weekly cleaning was provided with the long term stay. Some of the time I worked at the desk in the apartment which was quiet with the windows shut and not too noisy with them open, despite facing on to the junction of Neue Roß straße and Wall straße - just occasional busses and cars.
The staff were very helpful and pleasant and they all spoke English. The location on Neue Roß straße is very central and made it easy to get to most places in Berlin. Overall, I was delighted with my stay and it was the best place that I stayed in, during the 6 years I’ve been coming for long trips to Berlin, I highly recommend this place. I’m coming back to Berlin in 2022 for 6 months and I’ve already booked it.