My Partner and I recently spent four days in Cologne. I would definitely recommend Hotel Windsor as somewhere to stay.
The Hotel is approximately 10 minutes walk from the Cathedral and Station which considering some of the areas can be pretty noisy at night, staying away from the centre was a good idea.
We arrived around 11.30pm and the man on the reception desk couldnt have been more helpful, even guided us to a bar that was open so we could have a drink before retiring.

The room was brilliant, very spacious and clean.

The rest of the staff that we met the following day were also very friendly and always had a smile on their faces.
The breakfast was excellent. There was continental style breakfast along with fruit, cereal, bacon, egg, fruit juice and yoghurts. Coffee and tea was also served.

The only downside was there was no tea and coffee making facilities in the room, although they did tell us that should we ever want any tea or coffee at any time we only needed to ask and they would bring it to our room, free of charge.

I would definitely go back to this hotel should i ever visit Cologne again.