I stayed here in November 2012 for 2 nights during a conference. I liked the ambience which was relatively laid back. There were some great gardens around the building and the service was excellent.
The coffee shop was very useful and not at all expensive though I never quite got the hang of the opening hours.
The food was superb - one of the best I've tasted in a hotel of this grade. Breakfast was like a full English with a full German so you had bacon and eggs and hash browns together with prawns, pickled herring and a wonderful array of cheeses. In fact it was probably the best breakfast I've ever had in a hotel.
I found the room I stayed in convenient but a bit small. A plus was the fact that smoking was allowed in the room although I usually preferred smoking outside.
The only serious drawback was the hotel's location which was far from the city centre and as far from the city's attractions. One doesnt get much free time in a conference so it would've been nice to be able to pop into town or see the Rhine, I did get to go to Beethovenhaus however - well worth a visit!
Pricewise - it seemed reasonable enough to me!