Carnival does not have as many of the extra items onboard like surfing, rock climbing and zip lines. Also there are not the "name brand" places like Johnny Rockets. Depending on the kids on board they do seem to try to keep everybody active and give teens opportunities to meet their peers on board.
All I ask is a tall ship and a star to steer her by; John Masefield
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014, Regal 2014
Star Clippers: Royal Clipper 2015