Ku'damm -the (old) wester part is closer to the IC than the Hyatt.
See my opinion here:
http://www.flyertalk.com/forum/showp...postcount=1891

"Hyatt is more expensive than the IC. I don't think that this is worth it. I booked club and Hyatt club is at the same (poor) level than the IC. Rooms are spacious - however, the "grand" Hyatt rooms are about the same size than the "deluxe" IC rooms. Did not book a suite at the Hyatt and won't go back to this hotel - it is expensive and the overall value is worse than at the IC.

BTW, Potsdamer Platz is considered the "new" center of Berlin - besides some generic shopping malls there's nothing really charming, in my opinion. The "old" western part has more flair."