If this scenario seems classic, make no mistake, it's because it is: Stan Nicholls takes many pictures of the Fantasy to weave a relatively simple story, with very nice nice, very wicked villains and epic battles of good against evil. Yet, strangely enough, the writing is captivating even out on these agreed bases. The author is expert enough to keep the attention on a simple story, but well built.
Hard to say whether you'll like this cycle: it all depends on your tolerance for clichés and your knowledge of the Fantasy. Readers bleached under the harness probably find this agreed trilogy, Manichean and child. However, for those new to Fantasy, young people who enter this world, or those who are put off by the overly complex scenarios, Nightshade is an advisor reading.