Music is one thing I cannot say anything bad about. I mean, the guys in the movie are talented, so they sang well. I like the Man-Child Syndrome song. It was funny. And I admit some songs were better than High School Musical oldies.
About acting... well, it's comedy. It was meant to be a musical-comedy and when it comes to comedy, unless you are Gina Rodriguez or Alan Alda, it isn't about good performances. It may be just a stereotype, but as long as you have some sense of humour inside you, starring in a comedy thing is simple. Rarely you meet a comedy-performer with good acting too... But that is something not to talk about right now.
It was a fun thing to watch, really got me out of the routine. I wouldn't watch it again because a) I don't think they'd live-stream it again on YouTube and b) why not watch something else? There are billions of out movies waiting for me.
It was not a good movie when it comes to acting and performance, thing I love seeing, but it was fun and I can name it one of my musical-comedy guilty pleasures. There's no other reason why I'd give it 8 out of 10.