I spent one night at this hotel after a convention in Frankfurt and a night in Brussels at a "box" hotel. I wanted something different and that is what I got. This hotel is in a great location, I walked from the train station, excellent service and the only thing missing is air conditioning. They do have about 10 fans that you can have in your room, but they go quickly so I would request one with your reservation. It's very cool that each room is unique and mine was like sleeping under a giant hoop skirt that went under a dress. The 5 star rooms were not full and we were able to see them.
I've learned recently from other Europeans that we as Americans are very used to air conditioning and we would rather freeze in a room than have it just be comfortable. There was a heat wave when I was there, and with my room facing inward,the open window did nothing to circulate the air. If you are a light sleeper you may want to have ear plugs as the walls are quite thin and you can hear conversations.
This hotel is narrow so the rooms are at different levels and locations. My room had an A-Frame shape and I could hear conversations to the side of me but on the upper level of the A-frame! Overall I would stay here again just knowing now what to expect.
The very cute dutch girl (with the long name at the front desk) is excellent, very friendly and accommodating. She gave an excellent restaurant suggestion which I was hesitant about since I had never had Indonesian food: Kantjil En De Tijger. It was amazing. If you go, get a Rijstafels which is like a big sampler. We had the meat one. I'll write a separate review there. My biggest thing is to go eat where there are both locals and tourists, this fit the bill.
Finally, on my last morning I went to the Anne Frank House which was amazing, buy tickets on line first and reserve a tour time in English. I went at 9am and had a flight at 2:50pm-took the train to the airport and timing worked out fine.