Like some other review said, this novel are better than the anime version (if we ignore the grammar problem part, which the author did rewrite previously some week/month ago, I can see the old original version would be even worse, so right now at least readable, oh and since I help him edit most of the grammar error, aside from the POV problem so it no longer as hard to read, beside more than half of the problem those lower than 3 stars have been solved, at least for the grammar part)
The story show more realistic touch that the cannon didn't show, and less bias like the anime since the author do try to be realistic and also admit that American aren't perfect (another point is that he don't make some 'enemy' like china or north korea go full evil/retard, after all he recognize that it mostly the 'leadership' and not the people at fall here in real life).
and the story also begin to go way difference after volume 2 (the Italica siege arc) and become better there, only use the cannon for some reference but still go as it own story and add backstory and stuff that not in the cannon, while still consistent and interesting, so try to be a bit patient and read to at least chapter 25 or 26 to finally see more difference (and you can check the character list and map in author discord channel, you can see the author expand way beyond what the cannon world map show, and add more stuff like new city and place in that cannon continent map there and not just simply bland)
Although the author are quite new, but he have one hell of learning curve and do try to improve it, while being realistic/consistent with the story so it a plus, and it not typical self-insert and take the topic more serious, so mostly no otaku stuff (maybe the mc are a bit of nerd with western cartoon/movie like lord of the ring, transformer or similar, but that only slightly show it, oh and those character not bland, they do have lot of character developing, just a bit slow so you will see some major one in volume 5)
and there are actually some new enemy general that actually competent, and some real threat that modern army just not able to handle easily, so no usual easily streamroll there like most fanfiction or cannon