I enjoyed Youjo Senki's LN series, but the manga is just as good. What did the LN do really well in? It depicted a lot more of Tanya's monologuing which is lost in the manga, and there's also a lot more focus on Zettour, Rudersdorf, and a lot of different military personnel to really figure out why some military operation happened. However, honestly, other than the monologuing, I really did not care much for the worldbuilding. The manga focuses more on the details of battles, the characters close to Tanya, and dialogue. The manga essentially focuses on the good parts of the novel, while cuttingout the longwinded worldbuilding. All the criticism I had on the novel for having extremely lacking descriptions of many battles, whether it be the Rhine, Arene, Norden, etc, they're all fleshed out and actually are depicted in the manga. Visha, Grantz, Weiss, etc. All of the mages in 203 Flight augmented batallion get to shine a lot more brightly in the manga due to the focus on the battles, and even the slice of life content that's outside of the battles. In the end, the manga does choose to show different perspectives that were not shown in the LN, basically allowing us, the readers, to get a better understanding of the whole picture (good example is Erya).
Art looks great, at least character wise. Combat scenes are nice, but it's extremely obvious when real life photos are scanned in and heavily filtered to make it look like manga, and juxtaposing that background with more anime hand-drawn characters. It was really jarring to see anime/manga style soldiers fight real life looking planes placed under heavy filters to make it look like a drawing.
I did not like the Anime very much. Perhaps a 7, just because I like the source material. It rushes through all the events, completely just getting rid of any characterization or monologuing that Tanya had. The difference between the manga and anime is that the manga still explains and retains a lot of Tanya's original character while also fleshing out the side characters, details, and battles while the anime just flies through everything without giving enough explanation. The manga just explains the worldbuilding as little as it needs to and focuses on the juicy parts of the series, which is extremely smart. Overall, a good adaptation that deviates direction from the source material by a decent margin.