I relied on Ninja alone for all 4 sections. Everyone's experience and learning style is different so be honest with yourself about what works best for you. I personally can't stand lectures/videos and find myself losing focus after 5 minutes. What worked best for me personally was grinding MCQ. Reading the explanation for why I got a question right or wrong seemed to drill the concepts into my mind. I wrote down the explanations and would refer to them as I would go through questions as well. The fear of getting questions wrong helped me stay focused for hours at a time. That may not be right for you though. Hope that helps.
AUD - 86
BEC - 86
FAR - 81
REG - 87
Ninja Only
CA CPA & CFE
Currently studying for CAIA