Looking only at an outline of the plot, Dragonsbane could easily be mistaken for a yet another tale in the "high fantasy" tradition. It contains most of the standard elements that make such stories popular: heroic quests and battles, contests of magic, and the like. Those elements are executed well, and alone could make for a somewhat entertaining story.
However, the tale is anything but high fantasy. The heroes of the story are presented as human beings, with human faults and human needs, and nothing is as simple as the legendary ballads would suggest. As much as anything else, the book deals with difficult choices, past and present, that define who the characters are and who they will become.
In particular, I found that I could truly empathize with Jenny, a woman torn between her love for her family and her love of learning. "To be a mage, you must be a mage" to the exclusion of all else, she was taught, and every moment spent on other interests meant that much less power, that much less knowledge that she would never attain. Her struggle (and failure) to truly satisfy both of those desires is one of the central issues of the book.
Because of this and many similarly deep examples, Dragonsbane is a book that I have read again and again. Its conclusion brings a tear to my eye every time. Unlike most fantasy these days, Dragonsbane contains characters that are truly well drawn and compelling in their humanity. Those who read fantasy only for adventure and who have no taste for any "good literature" may well be disappointed by a book that focuses more on people than on swords and sorcery. However, for more mature readers who want more from a story than a few fights and lightning bolts, Dragonsbane is one of the very best books in the genre.