I've been reading quite a few YD stories over the past few years - mostly because I was trying to find books my mother would enjoy. It was due to this exploration that I happened upon the Ranger's Apprentice series. With that completed I naturally picked up Mr. Flanagan's new series.
Let's make a few things clear here, if you're looking for deep, philosophical meaning, don't read these books. You're not going to find, like in "The Golden Compass" or "The Lion the Witch and the Wardrobe", the author's take on religion. These books are fun, and full of adventure. That isn't to say there aren't lessons to be learned. The importance of friendship and working as a team are a strong theme through Mr. Flanagan's stories. Using your brain to think through situations is a trait common to the main hero in both of Mr. Flanagan's series.
One of the things that sets Rangers and Brotherband apart for me from other YD series is the presence of a strong adult mentor. In most YD stories the adults are either not present, completely useless or are just plain evil. I like this aspect of both series and admire how Mr. Flanagan can make our young hero the star of the story without losing sight of the fact that he is still a boy, he has things to learn, and having an experienced adult around to help him out can be a good thing.