It's intriguing work, well-directed and conveying an atmospheric feel of the "summer of love". Also, it's a magnetic portrait of Manson the man; Matt Smith does an excellent job, he's conveying a perfect balance of manipulative charm and danger.
The one slightly negative remark I have, is that Smits's performance sometimes overshadows the women at the center of the narrative.
But this is constantly exciting and well worth a watch. See it!