Just returned from a stay at the Hilton Amsterdam, and they do, sort of, take care of Diamonds.
Got a small room on the 8th floor with lounge access(10th floor). Lounge is amazing! Great view, nice food/drink, fantastic view. One morning when the lounge was full they gave me a voucher for breakfast in the hotel restaurant, which was realllllly good.
Small bottle of grand Marnier and a letter from the mgr when I checked in. Terrible problems with keys, had to get 5 new keys in the span of 5 days.
Staff was very friendly, nice turndown service with bottled water each night.
They did recognize Diamond status when I checked in. All in all, a nice stay.