Dawn or Gem? New York or Boston?

I am trying to decide between two cruises to Bermuda. Either the Dawn out of Boston or the Gem out of New York. I have never been to either Boston or New York. What have your experiences been at either of these ports?

i will be traveling with my sister-in-law and her 19 year old son. Also briinging my son who will be almost 14. I suppose both ships are good for teenagers, but what is your experience with either of these ships? Would you recommend one over the other?

Any advice is appreciated.