Part I was good, it had a straightforward story and everyone had their own decent screen time, it is perfect and enjoyable for the simple-minded.
Part II is more complicated, also there were more characters that was introduced which meant previous characters would have less screen time than usual. Part II mainly consists of plot twists, politics, Japanese mythology, storyline depth and many cliffhangers.
I love both of them, I liked how I don't have to try and figure out as much for Part I as I do for Part II, but that does make it more interesting. I'll lean towards Part II.