Disappointed
My wife and I stayed in Renaissance 57 hotel for 2 night in April. Overall, we did not like our stay there. Perhaps, we should have had lower expectations of this hotel, but we just thought it'll be as advertised on Marriott's web sites - nice and cozy boutique NYC hotel.
Location - perhaps, the only good thing we can say about this hotel. The location indeed is stellar. Close to main shopping and entertainment nodes in NYC.
Room - we had a standard double hotel room. I got the room for redeeming my Marriott points. The room was very small and dark. The furniture was old and worn out. There was no minibar, no robes, no slippers in the room. Most annoyingly, the size of the bed was very small, although we were told it's a standard queen size bed. Perhaps, such a small queen bed size is standard for NYC hotels, but it's clearly too small for two people. The room was quiet though.
Breakfast - available only a la carte. 
PS: I should admit that after I complained about the minibar, the personnel got us a small bottle of wine, and some pasteries as a complement. However, this could not improve the overall impression from the hotel. It's just not a 5 star hotel that we thought it is.