I finished this a little while ago, but lacking a computer at the time couldn't write the review.
The Keepers of Arden tells the tale of two brothers, Wilhelm (the elder) and Salvarias. Wilhelm's a good egg through and through, whereas his brother is a much more mixed bag (were it not for his elder brother's unconditional love one suspects Salvarias would be rather evil). Evil seeks to claim Salvarias, and sometimes uses his affection for Wilhelm against him.
The first half of the book focuses almost entirely on the two brothers, and adopts an episodic approach to their early lives. It works very well, helping to establish the relationship they have between themselves and with others. I shan't spoil it, but the way the story goes you can see why Salvarias in particular relies upon his elder brother, and how the return of that esteem affects him.
In the second half more secondary characters are introduced and the stage starts to shift from their home city to various locations. I feel a few more shades of grey or weak spots would have helped to flesh out the new characters (reminds me a bit of how I felt about the first Mistborn book's secondary cast, actually). There's some nice character progression for Salvarias, who becomes more independent.
There's an old school feel to the story. I'm not sure why, but it slightly reminds me of things like Outlaws of the Marsh, or even the more recent The Masterof Izindi. Anyway, old school is a good thing, in my (well LK Evan's) book.
There are no elves or dwarves, but instead a range of different, original creatures, and a mythology based around long-dead gods. The lore isn't thrust under your nose and slapped in your face, and is gradually revealed in a way that feels natural.
I felt that greater moral ambiguity would have helped things. Salvarias has a good dose and Wilhelm none (which is fine, that's Wilhelm's way), but more elsewhere would have been an improvement (this was a conscious choice by the author, I think, rather than cocking up an effort at more moral greyness).
Salvarias was clearly the best character. He got more little eccentricities (counting to himself, the puzzle box, lavender etc) and the most moral ambiguity of anyone. There's also an air that he might turn into a complete psychopath if Wilhelm got killed, or that he could drift inexorably towards evildoing. It's a good element of uncertainty.
Overall, I enjoyed The Keepers of Arden, and those who enjoy old school fantasy should give it a look.