We have taken the Circle Line cruises before but this was the first time we went on the Harbor Lights Cruise and we were not disappointed. The Circle Line ships are large and you can get a seat (arrive early for one on the outside deck, try the top deck at the front so you can grab a seat and just step through the front door to get outside for picture etc.). The cruise covers the Western area from Pier 17 down to the South of the island, past the Statue of Liberty and up the East side to the UN building and beyond with many sights to see, all covered by a very knowledgeable guide who relays information over a PA system which is helpful and not (for us) intrusive.
The lights are lovely and it is such a nice thing to be taken around the island in comfort - everything spread out before you with no rush.
We exchanged our CityPass slips for tickets on the morning of the cruise with no problems and I can recommend this and the daytime cruises and will do them again on a future trip to NYC.