Picking up the Throne of Glass and seeing the teenage protagonist on the cover, your mind gives you the imagery of what to expect.
It should start with a kick-ass female, who not only is physically skilled and attractive, but also highly intelligent. The setting appears to be bronze age, plus or minus magic, and the girl will probably be low-born but yet somehow become thrust into the world of the kings and princes. She will need to fall in love at least twice, with either best friends, mortal enemies, or two males who are so far apart in physical location that she will be forced to make the difficult decision. She will have severe teenage angst, and some type of flaw of character that she must overcome; perhaps the murder of her family, perhaps a long forgotten spell, or maybe she's just a little miss crankypants and has intermittent hissy fits when she doesn't get her way. And through all of this, the lovely protagonist will beat the hell out of a lottt of guys and save the way of the world, at least until volume two.
Yes, yes and yes! Maas delivers the goods! The writing is excellent, and the pages turn themselves. Since this is only book one, Caelena doesn't have the chance to beat up many people, but she undergoes her own serious struggles nonetheless. It's a five star book, because the author does what she is supposed to do. You know it before you pick it up, and you pick it up anyway.
So it's five stars and that's that.
If you don't like YA books, you shouldn't have picked it up. Does it matter that you can guess what is going to happen? Of course not. Does it matter that the entire premise (that an evil king who kills hundreds of innocent civilians would not immediately execute a mortal enemy) is faulty? No, you can ignore that too. The writing is THAT GOOD.
I found one grammatical construct somewhat overused--juxtaposed opposites. "I felt simultaneously hot and cold" or "heavy and light" etc. The first time I thought it was a cool turn of phrase. By the second, it had lost its originality. By the fifth, I had to stifle a groan. However, if that is the worst I can say about any novel, it clearly deserves the highest ranking you can give.
So my own "read" folder no longer suffers from a conspicuous absence, and if you are a YA reader, neither should yours! Get a book by Sarah J. Maas onto your shelf!