My husband and I stayed for 3 nights in this hotel in Dusseldorf in 8/07 on a vacation (not business). The hotel has a very imposing exterior, a big lobby (with overpriced internet), a helpful staff, very large, formal but comfortable bedrooms (black and white toile wallpaper with matching dust ruffle on the bed, flat screen tv on the wall, comfortable armchair with table next to small balcony that opens with french doors). The hotel staff was courteous and the concierge vas very, very friendly and VERY helpful. He pointed us to an internet cafe around the corner. When we asked about where to rent bicycles, he laughed and said the closest place was a 30-minute walk (a lovely walk), because the hotel is in a "big money area." Bicycle rental companies apparently cannot afford nearby rents. Anyway, after a walk down the Konigsalle (Dusseldorf's biggest shopping street with a canal & flowers running down the middle is filled with upscale shops like Guzzi & Louis Vuitoon) and then down another street with lots of cafes and bookstores. We rented bikes at Rad Ab (has a very helpful staff) . We rode along the Rhine Promenade (right behind the hotel) and crossed a bridge to a lovely residential area.The hotel's location is good because it is next to a big park, next to the Old Town and the Rhine Promenade, and a short walk from a metro station that's just 3 stops from the train station.
Overall, I would recommend this hotel -- the rooms were lovely and breakfast was great. (Ask about including breakfast when you book your stay -- we didn't ask and our breakfast wasn't included (25 Euros each for a big, good buffet). On the final day, I ordered breakfast a la carte and paid 8 Euros for very good muesli (with lots of optional toppings like pumpkin and sesame seeds and fruit) and a pot of tea - the coffee isn't good here.
If you rent on Expedia, watch out for significant taxes and extra charges that are added on at the end.