3.5 stars or 4...it doesn't matter much but since I gave The Blue Sword (that I read just before reading this - like 1 hour before) 3 stars, 3.5 is the least I can give The Hero and the Crown, because I enjoyed it much more than the first. 
 I don't know, the tone and style of the novel appeared to me to be more lively. I really enjoyed the characters and to learn more about Damar's history. 
 There is obviously a few heroic moments and yet I was less interested in them than in our hero's journey, that gets lots of point to be our heroine's journey. I thought the book, that was written a while ago now, proposed us some classics of the genre, as well as a few original way to deliver the story of a people through a feminine lense. 
 Sure, nowadays we have plenty of kick ass heroines, but you have to admit in "older" fantasy books, you don't see much of them and the way Robin McKinley does it is really centered about her heroine's journey as a true hero without denying who she is and working the same steps as any hero's journey while including what being a girl entails. 
 Truth be told, I found the male characters of this book more open than you could think of such a scenario and the subject of the king's daughter (instead of a son) is indeed treated but not in a "women are useless at everything and should be denied all things good". It's subtil but present because it's a lady's book and shouldn't be denied the title (that I give it ;). 
 There is no black and white. What Aerin faces, the choices that she makes, may not be perfect and don't have to be because the author does not give us a story where the goal is to get an utopian fantasy. 
 What the book does well is to put in perspective different issues as prejudices, role of women in society, class without preaching and getting in the way of the story. 
 And for having read The Blue Sword, you can appreciate how their society was built thanks to Aerin, dragon-killer, queen. How they did not denied her but evolved, positively, toward being a more open people. 
 For quite a small book (granted with tiny fonts - my eyes are all red) it really delivers a solid, heroic adventure story. You can very well read the Blue Sword after (or before) but The Hero and The Crown does not call for a sequel, everything is tied up. 
 (And in any case, the Blue Sword isn't really a sequel, more of a companion book because the story happens in another generation and is separated)