We booked this using the New York Sightseeing pass and were very impressed.
We were on a tight schedule as we had a lot to cram into the day, but we really wish that we'd spent a lot more time on this tour, as there was so much that we had to cut short.
Obtaining a ticket: Went down to Castle Clinton to get our tickets; Que was fairly long and once ticket obtained had to sit in another que for a while, as well as go through security etc. This was probably the most disappointing part of the tour; the waiting around as well as totally OTT security.
Once on the ferry, we went out towards the statue of liberty; great views and plenty of opportunity to snap away. The boat made a stop at the statue, but we chose not to get off and instead went onto Ellis Island. There, we enjoyed the museum in the building which was the first port of contact for many immigrants going to America, so this was quite poignant and very interesting and this is the part of the tour where we'd had loved to spend more time.
The boat itself was fine - however only 1 entry/exit door which meant loading/unloading took ages; surely should be 2 exits to speed things up a bit?
Overall, really worthwhile and would highly recommend.