Much like building a basement gameroom within an existing house, this manga series adds a lot of fun, excitement, and (finally) some cleavage to the solid foundation of the Girls und Panzer Project universe!
I discovered the Girls und Panzer series during the recent (sequestered) winter, and very much enjoyed the original content. Since, I've also soaked up what I could find of the additional content in the universe, some good, some not so much. For example, GuP The Movie was enjoyable overall, but (to someone like myself with a background in engineering) the sidestepping of practical physics took a lot away from the experience. As far as the different manga series, I've had the same thoughts. The first couple (especially the mangatazation of the anime) were written with to much emphasis on not disrupting the anime canon, and didn't bring anything new and were boring. Starting with "Little Army II" new characters and story lines were developed and were more interesting. Even "Motto Love Love" used the completely different (shall we say) sketch comedy format that brought new live and added some tasty meat to the established canon characters.
Now, (for the last couple of years, and just now winding up) there has been the "Ribbon Warrior" manga, which has brought the best new content to the project since the original series. Taking a few paragraphs from the earlier released "History of Senshado" essay (I don't have the source, but I believe it was part of the anime DVD package) Ribbon Warrior introduces a handful of new characters and a completely different format for tank combat than the more established and formalized Interscholastic Senshado Federation style matches.
Featuring light tanks and tankettes, with many fewer rules and restrictions, the Tankathalon matches are more like Brazilian Valle Todo (as referenced in ToraDora - look it up) than the structured etiquit of Olympic style Fencing. High energy and much more cutthroat, Takathalon matches (like WRS auto rally competition) allow spectators on the fields of competition, and "tuning" of the competition vehicles. The emphasis of the competition is now on innovation, psychology, and preparation since the ability to dominate the battlefield with armor and firepower has been eliminated.
Even the narrative style is new, as Ribbon Warrior, where the story is told through the eyes of the wingman of the title character, in a manner much like "Sherlock Holmes" is told through the eyes of Dr. Watson. Even the age restriction level (I suppose that's the appropriate term) has been bumped up a level: there is fan service here! Although certainly not gratuitous and never interfering with the story, it adds to the anticipation knowing that for the first time (except for the mentioned Motto Love Love comic strip) there are bathing suit shots, cleavage, and the rare groping within the main work. We are allowed to be aware that the cast of characters or 16, 17, and 18 year old young women with hormones, hearts, and some self-awareness of their bodies. We are also aware that the character designer has a (strong) preferences for slim athletic builds featuring larger bustlines.
Speaking of the character designer, This series (as mentioned in the previous review) is helmed by two of the lieutenants that were part of the anime team. This greatly contributes to the feeling that this work is definitely part of the same universe, but clearly has it's own direction and energy and really builds on the canon material without contradicting anything. The timeline for Ribbon Warrior seems best to fit between "The Movie" and "Das Finale" and gives lots of space and time to answer the larges complaint from the animated works which was that most of the dozens of characters introduced in the animes didn't get much if any developement. So far (I'm less than half way through the total work) most of those side characters have had plenty of feature time already and we have learned a lot more about these dozens of personalities that had so much undeveloped potential.
As you can tell, I am really enjoying "The Ribbon Warrior" manga as a great expansion on the "Girls und Panzer" universe. This is, I feel, the best work in the project since the original anime series. For some readers, it is in some ways even better. It is posted on MangaFarm and other sites I'm sure, and as always, support for the original artists is encouraged. Highly recommended!