If you want to see a good number of attractions in New York, the pass is DEFINITELY worth having. The pricing structure tends to mean it gets better value the more days you have and the more you do.
If you just have a passing interest in seeing a couple of things, just pay directly for those attractions, but if you want 3-4 days of full on sightseeing - get this pass - you will use it more than you think.
We ended up doing a number of things we otherwise might not have considered, simply because we already had the pass, and it didnt cost any extra to do them.
We wanted to do a number of the main attractions: 9/11 Museum, one World trade center, statue of liberty, empire state building, edge, downtown/uptown bus tour, top of the rock - and we did all of these and a bit more.
We managed to squeeze in the harbor lights cruise - and thoroughly enjoyed it, and did a couple of others 'just because' including Intrepid Museum, RiseNY, and the Museum of Sex.
We did also try to book in Escape Virtuality, but our itinerary just got a bit too full, so we had to cancel.
Overall, the pass was amazing value, costing us about 50% of what it would have cost to do each attraction separately without a pass. However, we might not have bothered do a couple of them if we didnt have the pass , but were glad we did.
Only 'downside' - and this is not a fault with the New York Pass - was the central park bike hire. By the time we got there at 10:00am the queue seemed to be about 150 people long and halfway down the street. After waiting for 10 mins and the queue barely moving, we figure it would probably take 1 - 1.5 hours to get a bike - so we quit and walked central park instead, as otherwise we would have run out of time. I guess you need to get up at the crack of dawn for the bikes.
We possibly might have done more, but we did not plan ahead, we just tried to wing it and get around the attractions as things happened - but some you have to book slots, and this meant a bit of hanging around between things.
I would recommend looking through all the attractions, working out which ones you want, and making a list/plan before you arrive - allowing extra time between attractions to allow for travel and queues.
If you go to New York, get this pass - you wont regret it.