I had a very enjoyable stay at the Berlin Marriott Hotel. The location is excellent, right at Potsdamer Platz, and the service throughout my stay was also very good. The room was spacious, modern, well equipped and very clean.
What impressed me most was how quiet the hotel was despite its extremely central location. There was a World Cup match on the day of my stay, and the atmosphere outside was very lively, with large crowds celebrating in the streets. Even in the hotel lobby, the match commentary was being played loudly over the speakers, which created a great atmosphere.
However, once I reached my room, I could hardly hear any noise at all. There was also surprisingly little noise around the hotel itself. Considering how busy and energetic Potsdamer Platz was that evening, the soundproofing was genuinely impressive.
Overall, this was a very comfortable and well-managed hotel with an excellent location, spacious rooms, modern facilities and remarkably good sound insulation.