I don't know what it is about him that got him so famous. Incredibly unlikeable star IMO, mostly caused by him being incredibly famous and having crazy fans for an OK singer at best. From what I've heard of the first movie, the main difference is new music and more mature incidents he'd gotten himself into.
The movie is just footage from his concerts, crazy fans, people talking about how great he is, and such. But I'd wait for it to come out on DVD and check it out for the library. Perhaps if you find his music fine(but detest him / his fame) than you might not completely hate the movie. So one reason it was unbearable was the fact that his songs were playing in the background nearly the entire time. Is Justin Bieber actually this popular among grown men? I either don't care for or absolutely hate his songs. I'm surprised that so many other musicians(who all have more talent than him) showed up in the movie. Sadly, there are enough that this'll make a profit like the first and he will not go away for a long time. He has an inflated ego and is desperate to stay in the public eye, that's obvious by this. Maybe if non-fans stop talking about him he'll go away sooner than later. DO NOT SEE THIS IN THE THEATER UNLESS YOU'RE A FAN. The single positive thing about me seeing it is that I can legitimately review the movie. But no, this has to be the most boring, stupid, unbearable film I've seen. Maybe it'll be an interesting look into his life or even 'so bad it's funny'. My "EX"-girlfriend was begging me to see this with her and so I gave in thinking it can't be too bad. Obviously if you don't like him, like most people, you won't like this movie. This movie is just another way to get him more money and to keep people talking about him. Terrible music, same incredibly unlikeable singer, same poor film-making.