Cruise Formal Night; Suit or Tuxedo 14 Year Old?

On a Disney Cruise on a formal night it said to wear a tuxedo or dark suit. When I go I don't know of I should get a tux or a suit (cuz currently I don't have either). For a 14 year old boy, would you a) find him better looking in a tuxedo or suit? And b) which would you think is more suitable?