It's Bocchi the Rock, but this time it's a movie. What more is there to say?
In all seriousness, the two films (Re: and Re:Re:) are worthwhile viewings for any fan of the series. If you can catch them in theaters, it is a wonderful experience, watching Bocchi on the big screen and hearing the music over loud theater speakers. If you can't, it's still a worthwhile watch for a few new scenes and songs, and the movies' unique framing of the story.
The movies (especially Re:) are framed differently from the series, and it was interesting to see how they were compiled for a theatrical experience. A few of the moments that are less central to the overall story were relegated to montages featuring some songs from the Kessoku Band album that previously weren't featured in the anime. One episode, however, was totally cut (the one where they go to Bocchi's house).
I didn't feel like these changes hurt the experience, as the movies clearly were meant to focus more on Bocchi and Kessoku Band's overarching story and less on the fun slice of life moments (of which there are still plenty in the movie), and I feel they succeeded in that. That being said, I'd recommend that someone new to Bocchi the Rock watch the series first before watching these movies.
The final scene of Re:Re:, where (spoilers incoming) the entire series is rewinded back to when Bocchi was an elementary school child, was very touching as a Bocchi the Rock fan. We see Bocchi's growth in reverse, which makes you really realize how far she has come. A perfect ending to a movie all about Bocchi and her growth as a guitarist and as a person.
Let's hope that, following the success of these films, a Season 2 is announced soon!
