My boys really loved the Odyssey (haven't been on Wonder, but have been on Symphony). They loved the bumper cars, the sky diving simulation and all of the teen activities including that the teens had their own outside deck.
They had a great time on Symphony as well, but said they like the Odyssey better. As others mentioned, if they want to do sports stuff, the Wonder would be better. My kids aren't sports kids.
They were 18 and 13 on board if that helps. But honestly, can't go wrong either way!