I have just finished Duel at Araluen, book #3 of the Ranger's Apprentice: The Royal Ranger series by John Flanagan.
As I said, highly reminiscent of Siege of Macindaw, but with enough differences to keep a tactical mind churning and learning new tricks. Skill with the bow and blade is excellent, but flexibility and imagination are what marks the best commanders. I have to hand it to Maddie; she makes a good princess, but a better Ranger - and those patriarchal Red Fox Clansmen deserved every arrow she sent them. That said, the Ranger Corps has got to make the sling an official weapon of theirs.