First off...I just want to say that I HATE Little Pete with the intensity of a thousand suns. I hate almost every character like him, that serves as little more than a burden to more important characters...but in Pete's case, they also made him the most powerful in the entire f***ing series.
Second...I WANT to like Sam and Astrid, I really do...but they're the f***ing Jack & Kate of this book. And let's be honest here...for all his tough talk, Sam only ever seems to take REAL action against people who really AREN'T threats. But Caine nearly destroys everything in book 1: I'm not gonna be a killer. Drake returns and is all but unstoppable in book 3: I can't kill Brittany, even if she wants me to kill her to stop Drake. Then he has no issue with Hunter or a whole other bunch of B.S. And Astrid is just as bad. Can't kill Nerezza, but could kill Little Pete.
Meanwhile, Caine and Diana are just so much better of a couple...until that last book. Like...their relationship was interesting through the first four books, and then Diana gets pregnant and becoming a God mother or something dumb like that and her entire awesome personality is destroyed. Caine's still cool though, and I like how he's far more about action than Sam ever is, and how he's slowly becoming more sane as the series goes on, while not becoming too overbearingly sane.
Albert...I respected him so much early on...but he's become a little b****, and I really can't stand him anymore. Meanwhile, Quinn has gone in the exact opposite direction, getting better and better as the series continues and he becomes more confident in himself as a fisherman.
Sam's freaks are all likable to some extent. Orc has become far more appealing as a character since the end of Plague, and I appreciated the fact that he at least gave Howard a proper send-off, since I appreciated Howard's scummy character. Dekka's wannabe lezmance with Brianna is adorable and I like Dekka and how strong she is...more than Brianna, honestly. Breeze is just too cocky sometimes, and it gets her into trouble far too easily. And then Computer Jack is okay...but kinda just there. As for Taylor...I'm not even sure what purpose she's supposed to serve anymore, because the direction they've taken her character is just f***ing bizarre.
Now, the three characters I love unconditionally are as follows:
Edilio, because he stood up to Sam in Fear, and he's just been extremely reliable in every book thus far (hell, doesn't he almost die, like, every single book?).
Lana, because let's face it, she's the biggest badass out there, she's never annoying or self-pitying or overbearing as a character, and she's just generally amazing whenever she gets a scene.
Sanjit, because he flew a f***ing helicopter and shortly thereafter started macking on Lana, with great success.
Anyone else, I don't really care enough to mention.