I spent 6 nights in mid-July at Arte Luise Kunsthotel, in Berlin. Excellent, helpful staff at the reception desk who all appear to be fluent in English. Very high standard of cleanliness maintained in the bedrooms. Helpful and clear information about baggage storage facilities before check-in or after check-out. A major plus is that guests' choice of type of breakfast can be changed from day to day - so you are not committed to a major buffet breakfast for the duration of your stay, as is the case with most hotels.
Reichstag, Brandenburg Gate, etc., all within easy walking distance. Alternatively, to go further afield in Berlin or to go to Potsdam - or eventually, to go to the airport - the Friedrichstrasse Station is also easily accessible.
The sight of an elevated railway line running by one corner of the hotel was initially worrying. However, I was out during the day and if trains were running during the night, I certainly never heard them. Neither trains or other guests disturb my sleep at any time.
I appreciated the effort which had gone into developing the artistic theme for the hotel. I only experienced the van Gogh room but came away with a greater interest in him.
Clientele seemed to be drawn from the full range of ages.
I will be very happy to return to the Arte Luise Kunsthotel when next in Berlin and would have no reservations about recommending it to family and friends.