I had a lovely stay at the Copenhagen Marriott for 4 days, with a room on the 4th floor facing the street that leads to Tivoli Gardens, which was a great view lit up at night. I was concerned about noise, but that was never an issue. The location of this hotel directly on the water is enviable. There is a lovely multi-level deck with chairs and bean bags for guests. The dock itself was a popular hangout spot for the Danes. My friend and I came back to the hotel one day to a dock party to the side of the hotel, with families, some kids, and many adults. We sat on the dock with a glass of wine and enjoyed the 90s music playing through the speakers.
The room itself was spacious and clean, with a comfortable bed. The lobby was well kept and the staff was helpful, if a little befuddled at times. We rented bikes directly from the reception, but it's important to check the bike beforehand. Some had flat tires. Don't let the receptionist hand you keys without having picked the one you want, which was very easy to do as the bikes are lined up directly outside the lobby entrance.
We also tried the sauna in the women's locker in the gym, and could have jumped in the canal. There were ladders into the water. Directly across the way was a kayak rental place.
All in all, I would highly recommend this hotel.