I've stayed at this hotel twice on business, the first time in a suite and the second was a smaller room (think it's called Classic room). First impressions were really good, beautiful setting, stylish and really nice rooms. Reception staff were also friendly and helpful, especially when they couldn't find my reservation during my first stay (I think that's why they gave me a suite - as they had no idea what was really booked!). Breakfast was also varied and nice.
The hotel is very far from the city centre so don't stay here if you want to be central. There's also no gym although they might have a pool (not sure though).
What I didn't like about the hotel was:
1. The restaurants. There are 2 in this hotel and believe it or not, neither of them serve a vegetarian main course. I did try one of the restaurants and had a fish meal once which was really nice, but as I'm not a big fish fan I had to take a taxi to a nearby mall and eat there on my other nights! For a 5 star hotel, they didn't even offer to make me something vegetarian even though they were aware of my request. I also had a virgin daiquiri which was disgusting.
2. Nothing is written in English. I understand that the hotel's in Germany but come on - they can't expect all guests to speak German! Honestly, nothing in reception is in English and the leaflets in the rooms are all in German, except the limited room service menu which has an English translation.
3. No iron in the rooms and no irons available to do your own ironing. I found this appalling as they expect you to pay them to iron your clothes, and it's not exactly cheap either. The second time I went, I took my own travel iron!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC