The last of the Codex Alera, First Lord's Fury is a lot like the others. By this point, one just accepts that Tavi is super-human, that nobody we care about will die (I'm not quite done with the book, but I feel safe making that assumption), and so on.
I think that it's good that Butcher finished the series here -- I certainly would've stopped reading, even if he hadn't. For all their flaws, I think the "Dresden" novels are more interesting than the last 3 "Alera" books. I guess my problem isn't any one thing that Tavi does; it's that he's a brilliant tactician, inventor, diplomat, and, in the last two books, incredibly powerful to book; Tavi's role should ideally be split among three people, each of whom could also be wrong sometimes. I think Tavi only ends up being wrong on a significant scale once in the whole series.
I'm labeling this one disappointing not because I hated it, but because I was hoping that Butcher would somehow surprise me in the final installment. Instead, it's pretty competent, average work.