Codex Alera is a nice fantasy story, taking place in Alera, a realm strongly resembling the Roman Empire. The magic system is the best i have encounter, save perhaps the one of the Night Angel. The characters are well built as well. I got really close to them,and completely understood their emotions and decisions. Unfortunately, that's where the good attributes stop.
“Living was a dangerous past-time, and often quite painful—but there was also such joy in living, such beauty, things that one would otherwise never see, never experience, never know. The risk of pain and loss was a part of living.”
To begin with, the story is too Goddamn long. All of the story arcs, and i do mean all of them, are far stretched. I really got tired after the 3rd book. Thing is, far stretched arcs weren't enough for Jim Butcher. He had to keep repeating the same topics. I swear to God, i got sick reading about a female character who loves a male character, but can't be with him because she can't bare him a child. Thoughts & discussions about it lasted more than 200 pages in the whole series. Another really big problem i encountered is that there were a lot of cliches, and no surprises. Everything was predictable. In a trilogy this is not a big deal, but in 6 books? It's really frustrating.
All in all, Codex Alera is a nice fantasy series, but it doesn't belong in the top of your TBR list. Leave it for some other time...