HAve stayed in three places and no problems with any of them
ArtOtel near the K'damm (west Berlin)
Marriott Berlin via Priceline
Hilton Berlin via Priceline
Marriott and Hilton are both near the "main" attractions but are full service so things liek Intenet, etc. are overpriced.
ArtOtel is funky and kind of out of the way, but lots of good restaurants nearby