The real problem with this hotel is the location. It is very close to the main station, and so convenient for travellers, but the area around our big stations in Europe have become run-down and sleazy and this is worse than most. It wasn't so much the gambling clubs, strip joints and live sex shows, but the junkies and alcoholics on all the corners that were the problem. I never felt really unsafe, especially with the very obvious police presence in the area, but it wasn't very pleasant walking back at night.
My room was very comfortable (modern minimalist decor, flat screen tv, excellent shower room) but faced the street right opposite the goods entrance to the DB headquarters, and the noise of rattling trolley cages delivering goods continued through the night.
The reception staff were charming. I note that they now offer free breakfast on their website but I didn't get that deal - I was told it would cost €12, and I didn't bother. The hotel isn't exactly cheap and its plus sides weren't strong enough to make me want to go there again.