We got our entry as part of the New York City Pass which made a group of attractions very reasonably priced, we decided to head here very late at night as we arrived in NYC very late and wanted to see the skyline in the dark, we are SO glad we did! The wind was bitterly cold but my word was the view spectacular as it was a crystal clear night! Not only is the view incredible but the building itself is great, very well maintained, the marble work is gorgeous, reading about and seeing pictures of how it was built was a brilliant touch, the staff / security who guide you in the correct direction etc were also fab, very polite and happy despite it being so late at night... oh and it was super quiet...
Bonus! Of course this is a must see attraction for any tourist.