A friend nagged me to read the 'Youjo Senki' LN after the anime, so I started with the fan translation that’s been floating around. Honestly, I hit a wall around volume three. The prose gets really dense, lots of military jargon and economic policy discussions that made my eyes glaze over. I started cross-referencing with the official Yen Press volumes, and the differences were noticeable. The fan version isn't 'bad', per se—the core plot is all there—but it sometimes simplifies complex sentences or misses subtle connotations of Tanya's internal monologue. You lose some of that bureaucratic sarcasm that makes her character so uniquely terrifying. For a casual read to know what happens next, it's serviceable, but if you're really into the nitty-gritty of the world-building and Tanya’s twisted logic, the official translation is worth the investment. I ended up buying the first few volumes physically because I wanted to support the series anyway.
That being said, the fan translation’s speed was a big draw when the official release lagged far behind Japan. Some later fan-translated volumes felt smoother, maybe because the translators got more familiar with the material, or maybe I just got used to the style. It’s a mixed bag, heavily dependent on which volume and which translator group tackled it.