Its the hardest boss in the series to learn, thats for sure.
It has alot of direct nods to challenger runners "you can't do that shit anymore".
For example:
See how in this fight, i just walk round the backflip, to make sure i position right for a backstab.
https://youtu.be/VYLvwkgvFfo?t=3m20s
Well this boss has a nasty tricks up it sleeve to prevent that, if you try it, its got very clever AI tbh.
Now I'm excited! I better make sure to go to NG+ 4 at least with one of my characters.