I'll be honest, I kind of don't think this is that great of a question. Navigator Personas tend to inherit similar skills from the previous games Navigator, if not reusing the same exact skills. So I can't really respond with anyone other than 'Futaba', because for the most part she is just 'Fuuka and Rise but better'.
The only instance where I can really think about this is in terms of the infamous PQ, which actually gave the option of two Navigators with their own skills. Here I would say Fuuka, her buff and heal skills I just find more handy for a pinch.