I watched the Bang Dream Live Movie today, it made a nice ending to the three series. There isn't really a story to the movie, it's an outdoor concert where five of the bands from the series give live performances and each band performs three songs, which thankfully are subtitled. While I wouldn't say any of the songs were particularly memorable they're all quite nice songs and some have really good lyrics.
Bang Dream is a massive multi-media franchise covering anime, manga, visual novels, video games and CDs
Overall I found the series engaging and enjoyable to watch and rather different to the usual "high school girls get together and form a band" series, yes, it starts like that but the other bands soon enter the story and it becomes much more about the progress of each band and their interactions with each other. None of the bands are high school club bands they're all independent of the school, I suspect that the school element is only there as a link between the bands as several of the members of each band attend the same school.
This is certainly a series I would be happy to watch a second time at some point.