Girls und Panzer's side story about Maginot school, an inconsequential school that wasn't even shown in the main anime series, if I'm not mistaken. Overall, it's alright, and nothing was terrible, but it's just that Maginot is kind of weak and has little relevance to the story, so learning about Eclair and her changing tactics, well, it's kind of not useful worldbuilding since you're never going to see her in the main series again. The fight itself is fine, and there's a decent amount of strategy and phases to the fights, but it was kind of predictable how the fights were going to end up.That being said, you can say that for the main series as well, since Ooarai never loses, but this is doubly so against a team that's in the midst of reorganizing and changing to new tactics.
I actually find the art to be a bit worse than the other Girls und Panzer spinoffs, but overall, just an average read