I stayed at the Renaissance Amsterdam last October for two nights. Visited the Marriott while in town, but cannot offer any observations on the accommodations there.
In my opinion, the Renaissance was alright, but not what I expected, as it is rated a Five Diamond property. The location was great, however. Within 3-4 minutes of the train station and the major thoroughfare of street level storefronts, pubs, and restaurants. Not very far from the Red Light District, either. I did venture over there on the first night, out of curiousity more than anything else.
The rooms there are clean and adaquately appointed, but nothing special. The corridors are brick, which is kind of cold, I think. We made use of the lounge on the 6th floor which has a reception in the evening.
The two hotels are about a 10-minute trolley ride apart. The Marriott is right across from the main casino in Amsterdam.
Location wise I give a thumbs up to the Renaissance.
AtlMan