I'm surprised your agent didn't provide you this information, but depending on when and where you want to go as well as what you like, Carnival, Princess, Celebrity, and Holland America also go out of the NYC area.
As for the Explorer, we've been on it plus many other RCCL ships, including 2 other Voyager-class ships.
Personally, while I agree they are not quite up to Princess, they are still very nice. I think there are others coming out of the area that are also nicer than the Explorer - for example, the new Quantum of the Seas will be sailing out of Bayonne. Can't wait for that ship!
But you might also want to give NCL's new ship, the Breakaway, a look. It might surprise you.