You get transportation to the island with the statue. You got a audio tour that was very comprehensive and self-paced. You got to walk around at your leisure. There were Park Rangers that told a more animated version of what you heard on audio available for tours. You need to get there very early to get a ticket to go up in the statue. We got there at 10 and our ticket time would've been 2 o'clock. Ellis Island was closed at the time of our tour so we didn't get there.
The smart thing we did was we took the boat to the statue island and then took the another boat to drop us at Manhattan. That avoided a bus cost.