Here is some feedback for people who are planning to do some attractions in NY and are doubting about paying per entrance or buying a pass that offers entrance to multiple attractions like the Empire State Building, Top of the Rock, Moma and so on.
We would definitely recommend the New York Pass.
It offers a variety of attractions to do and you can easily evaluate if you gain by buying the pass or paying per visit.
The price of all NY attractions is rather high, so you will make quickly (a lot of) profit.
Since it was our first visit to NY, we decided to do a lot of attractions per day to get an impression of them, instead of doing a few attractions in detail.
If you are planning to do only a few indepth-visits, then no pass is suitable to you, in all other cases the NY pass should be your first choice.
However, as New York is big, you should plan your visits beforehand, so you can do the things that are close to each other on the same day,
and not loosing your time in transfers between attractions that are miles from each other .
You get also fast access to a lot of attractions (like Top of the Rock), just make sure that you take the right queue when entering an attraction or museum.
People tend to choose a queue quickly (especially when it is crowded), instead of searching for the signs that say 'NY pass holders here'.
We were very satisfied of the New York Pass and will buy it again when we visit New York.
Unfortunately for us, we visited NY in the week during the Sandy storm, which forced a lot of attractions to close.
The 'New York Pass'-company however was extremely fair and correct in dealing with this situation : they refunded us the days that we were unable to use the pass due to the emergency situation. A lot of companies would not bother!