My boyfriend and I spent three nights on the way back from Tanzania. The room was fine but the atmosphere was not our bag. It seemed predominantly a business and tour bookings hotel.
Neither of the restaurants were much chop -- I really wasn't after a tex-mex, American Indian themed dinner in the middle of Nairobi (nor piped elavator music for that matter).
That said, the staff were great and grounds quite lush... there was nothing really terrible about the hotel and when booking I did find it really difficult to locate alternative, more boutiquey accomodation in central Nairobi without spending a fortune. (We ate dinner at the Palacina restaurant one night and the food/ atmosphere/ live jazz band were superb -- no idea about the rooms though.)