The Marriott is much better - at least 2 to 3 classes than the Radisson-SAS.
It's a boutique hotel. The location is in the heart of Hamburg.
You can walk to all "Galleries", nice, upscale shopping areas with restaurants.
In one of the galeries is "Moevenpick" (=several medium price rest.) in another is "Petite Delice", a gourmet restaurant on the fleet (=canal).