This movie should please a wide audience of non-musicians. I am not a musician but I've seen movies based on things I know very well and it's always exaggerated and unrealistic and it usually bugs me more than other people; I can easily imagine how real musicians may dislike this one.
The directing and acting are great (although J.K. Simmons steals the whole show) as are cinematography and sound. However the whole premise is wildly unrealistic, and the moral of the story "to be great you need to be pushed beyond your limits" is a tired trope that has often been done in a better way than here.
On a personal note, I hate bullies with a passion and there can never be a "but it's for a good reason" excuse for bullying.
