Again link please on the novel saying it was weaker then Raikiri?based on the novel! and common sense
So far via the stuff we got for it it has more advantages then the Raikiri.
It isn't something mind boggling either since Kakashi made both of the moves and while Raikiri was formed when Kakashi was a preteen, PL was formed when he was Hokage and had more knowledge and experience under his belt.