Difficult to judge the service since I arrived after the reception had closed. However, the hotel had provided access to a keycard and the registration documents were waiting for me on the desk. Though I had to provide my own pen.
The room was good, well cleaned, though the TV was hanging at a 30 degree angle and the remote was extremely unresponsive. Didn't matter much since I went more or less straight to sleep anyway.
The breakfast was great - but don't be afraid of (or allergic to) dogs, since the (very friendly) house dog came walking around, begging for food from the table.
The price was exorbitant for the room though, but it's the law of supply and demand - don't go to Bonn during major conferences... ;-)