How I Use It
I started using Brainpop Science because my school bought a general BrainPop subscription, but I quickly gave it up because it looked too childish for my Middle School students. And that wasn't my first opinion, but theirs. Moreover, I think Brainpop doesn't bring anything new to my classroom. It just provides very simple cartoon videos that explain concepts without making students think or inquire. You can find dozens of videos in YouTube much better than those (and more realistic). The quizzes that complement the videos are just regular quizzes, with questions that just check students memorizing skills, but not actual comprehension.
I think Brainpop must be useful in Primary School, as a complement in some cases. But I don't think is an appropiate tool for Middle School (and of course not for High School) Science classes.