I think it's only fair to give a bit of feedback, having just completed my trip to Berlin. My thanks to Flying Lawyer, who a couple of posts above helped me decide to book the Intercontinental. It was an excellent choice and I was amazed at the range of Platinum benefits, which I did not expect. An upgrade to a deluxe room, free soft drinks and snacks in the room, a Marlene Dietrich branded sketch book and drinks for myself and companion at the bar, which were not bound with endless restrictions (in the end, I had a large Berlin microbrew pale ale). I actually slept well in the room and it was possible to open the window to get some air without too much noise from the exterior.
The other hotel I tried was the Indigo Alexanderplatz, which was also good with very friendly staff. Here I had an upgraded room, free minibar and gherkin snacks (which I forgot to take with me) and free drinks at the bar for my companion and me. However, I the room turned out to be airless and hot, but opening the window exposed us to a lot of noise in the Alexanderplatz area (which I found rather soulless). It didn't help, of course, that we had eaten a bit much and become plastered in one of the beer halls! Don't think I would go back to the Indigo but will try somewhere else next time.