Sheepfarmer's Daughter by Elizabeth Moon
It started off quite promising: girl goes off to join a mercenary company to avoid marriage. Unfortunately, it devolves into long sequences of battle maneuvering rather than focusing much on the story. I feel so cheated out of character development. I also didn't like the amount of characters that died, but I suppose that's to be expected in a war book.
I'm not sure that I want to read the next in the series as I became less and less enamored with the book as it went on. I am sure that some people will like the battle sequences although I don't have enough military experience/theoretical background (read as none) to determine whether the fighting is realistic or not.