My Take
My overall opinion is positive to enhance topic already taught as well as an assessment tool.
How I Use It
I have used Brain Pop Jr. for many years. It was especially helpful when I was a substitute teacher and lessons were not provided or extensive enough. I have used it most recently in my 12:1+1 class as a review/enhancement of previously learned materials. I especially like using the supplemental activities (ie. word wall, games, drawing...). My students especially enjoy being "the teacher" and leading the video/quizes.