Then you should enjoy the book (least, I hope you will).
The two schools covered - Tendai and Shingon - both teach the same goal (Enlightenment) but with different approaches. They use the same magic and the differences are theoretical and philosophical rather than mechanistic. They certainly aren't cults, but they do teach different spells, different skills and different ki abilities. In terms of goals though, its as you describe.
I did read back through 'Land of Ninja' in preparation for this book, but I have to say I was disappointed with its treatment of religion. To be fair, though, Bob Charette did caveat the lack of realism heavily at the start of the book although I got the impression he was far more interested in the samurai and ninja than in the religious occupations. Bushido handles things much better, but still with a lot of inaccuracy.
I won't pretend that 'Land of Samurai' will be 100% accurate of course; had limited time and space available, but I've done a great deal of reading, cross-referencing, head-scratching and so on, in trying to represent Buddhism is well as I could. It won't be perfect, but I hope it doesn't disappoint, either.
