As far as I am concerned they are both different. When I was learning all about WDW, I went to the Library and borrowed all the tour books. I loved the Unofficial Guide, it has great info. BUT...........when it comes to actual trip planning, the Passporter wins hands down. (I don't think the Library had the Passporter, I found it online)
I like the Passporter when planning my trip, not even that I really need it anymore, but just love to use it to organize everything etc.