This is for the six books in the series. Middle of the road attempt.
There's some good, some bad, some really bad stuff in here.
First, the good. The books, and a lot of the characters are a lot of fun. They have no grounding whatsoever in reality, but they're pretty fun. The story evolves over time, a bit too easily for the main characters, but it does evolve. The description of hardware in the book is pretty accurate, both the firearms and military equipment. The main characters like to read and learn, so it provides the reader with information as well. I actually wanted to know what happened next, until the last few books.
The bad. These kids are supposed to be 13, but they're pretty obviously not. No kid is as smart, tough, driven, well adjusted and awesome as the author pretends these are. It's just not in the realm of possibility.
The only real allusion to their age is that sometimes they throw temper tantrums and break stuff. Or the sophomoric jokes that run on WAY too long. An example of this is when they run into the tigers. From then on, it's a multi book spanning joke about calling the tigers "big (slang word for vagina)" I can't put the word in here cuz Amazon will censor my review, but it's thoroughly beaten into the ground by the time book six rolls around.
In the beginning of the books, resources are fairly strained, but as the books trend onwards, their numbers grow, but somehow resources become less constrained. It makes zero sense.
There's more, but on to the really bad stuff. First off, the pedophilia. Let's start there. One of the main characters, keep in mind he's 13, is hooking up with a 24 year old, and it's all rationalized away with, "Oh, he's really mature for his age." Completely disregarding the double standard that if the genders were reversed, the outcry would be loud and well deserved, that's the kind of logic a pedophile would use to justify their actions. "Oh, he's really mature for his age." That's gross, dude. The book could have worked just as well if the characters were 17-18 years old, since they act way older than that anyway, and there wouldn't have been any of the creepy kid touching going on here. Which means the author kept it in on purpose, for whatever reason.
Lastly, the main characters are complete psychopaths. The author rationalizes it all away as childhood shenanigans, but wow is it not that. Some of the earlier examples are charming and hilarious, some of the later ones are anything but that.
They bulldoze anyone in their path with violence, and everyone is happy to bow down and worship them. They murder innocents on multiple occasions, and show no real remorse. Several characters comment, "If the apocalypse hadn't happened, they'd have ruled the world." and they DON'T seem to think it's such a bad thing. It would have been. They're way off the reservation.