We looked into buying the various passes when we went to NY in 2011 (and are going again this July), but didn't really feel as if we would get sufficient value from them.
That said, the Smart Destinations website will also let you customise passes so that you only pay for the attractions you want, and they tend to be valid over a longer time period (for 30 days rings a bell). We did buy these when we visited Boston (we visited the Science Museum, Aquarium, Prudential Skywalk and had a DUKW Tour) which saved us some money and also let us skip the queues at the Aquarium and Science Museum.
NY is quite easy to walk around being on a grid system, so it is quite difficult to get lost. We did buy a 72 hour all-loops bus pass which we made good use of - we got to see most of Manhatten plus Brooklyn, Harlem, and also saw the city by night, and felt that this was good value (although it is possible to travel around for much less using the Subway, but then you don't get to see the sights!!)