They really are identical except for the theme. Both are part store, part restaurant, both have audioanimatronic figures, both have an event (rain storm/meteor shower) and the food is similar at both. We've been to both and like them equally. I'd say pick the one with the theme that sounds best to you and go with that one.
As for your teenager, mine love T-Rex. DS15 and DD17 both requested that we go again on our upcoming trip! It really isn't babyish at all...in fact some younger kids might find it scary with the large dinosaurs and loud noises.