I understand fully well that a hotel is not responsible for the noise outside their building, but it will still affect the impression of the guest's stay.
The rooms themselves were fine, we were a party of 15 people and my female coworker and I got some of the better rooms. Our male coworkers seemed to have issues with space, that it was very small with nowhere to open their suitcase.
I had no such problems.
The staff was very polite and helpful at any time, and room service did a wonderful job of keeping everything clean. I would give the full points for cleanliness, everything was so tidy and neat.
Breakfast was also a pleasure, I can't have dairy and was very content to see that they had soy milk and soy joghurt, as well as fresh vegetables and great coffee. They had assortments of breads and rolls, various cheeses and cold cuts, müslis and cereals, fruit mixes (not sure if it was fresh or canned), fresh scrambled eggs or boiled eggs, sausages or breakfast meats.
My main issue staying there was the noise, or that I couldn't open my bedroom window at night because there were smokers in front of the hotel and nearby, and the smoke would get into the room. It was very loud with the windows open, and even though it was September, the room was relatively warm. I had to choose between trying to sleep in noise, or trying to sleep in too warm a room. My earplugs helped somewhat, but not entirely. Perhaps for a shorter stay it would have been ok, but since we were there an entire week working at the Cologne Fair, it was very draining to not get enough rest.
I suggest very strong earplugs for a stay here.
Pro: very central, you can walk to the Cologne Dome from here
good connections to the subway or train
good service, qualified staff
nice breakfast spread
Cons: Very loud at night
poor WiFi set up (connection breaks often, bad when writing busines e-mails
or talking with clients on Skype.)