The most important parts of any book for me are the characters. This trilogy features a large cast of very unique characters who are brimming with personality, flaws, virtues, vices, pridefulness, insecurities, and humanity. The character work in this is second only to George R. R. Martin in its depth and authentic feel. MR really makes a world full of dragons and fire wielding makes them feel believable and rich as the characters are going through struggles, forming friendships, experiencing losses and hard truths, and striving toward triumph. Through each twist in the narrative, the characters are guiding the way rather than just being pushed forward with the plot. Every action has consequences and things that happen in the first novel were still strongly impacting the last.
My only complaint with the trilogy as a whole is the handling of rape. In the first novel, a character is raped, but afterward that rape is framed as though he was the rapist rather than the victim. I'm wondering if MR knew a rape had occurred but couldn't fathom the idea that a man could be raped by a woman. So she referred to it as him raping the woman who kidnapped, drugged, and forced sex on him. Since this was written decades ago, I wonder if the author's views have changed on this subject.
Changing views from different eras aside, this series has been excellent. I'm surprised I don't see it discussed more often.