After having tried many hotels in Duesseldorf I chose the Radisson Blu which is located quite centrally in town. The Hotel is big and provides a nice and modern lobby. The rooms have apparently been recently renovated. The result is a reasonably modern and stylish place, however a bit discretionary. Room furnishment and equipment is fine, beds are good, bathroom spacious, even though I would prefer a shower to a bathtub. If you're into sleeping with open windows - this is not the place for you. The surrounding is noisy with busy streets and tram around.
Despite all renovation the hotel itself can't deny its origin in the 70s - low ceilings, the "wellness area" is shabby and small. Breakfast at € 24 is audacious.
Staff is very friendly and helpful though a bit struggling with the number of guest in the lobby restaurant.
All in all a good place to stay for a short business trip - nothing really to complain about. However, there are more fancy or nicer places around for similar prices.