I am giving this book 2.5 stars (and 3 stars on websites that do not accept half stars), because 70% into the book, things began to get interesting (the premise was good too but that's it). Also, overall it's an easy & fairly entertaining read - consider this confession as the confession of a guilty pleasure. I can see why people like it, and I can see the book's commercial appeal. Unfortunately, all of this was not enough to make me a fan or make me want to continue the series (I rarely want to continue series that are longer than a trilogy in any case). 
 Am I disappointed? Yes, but mostly because I have heard so much about the book, and I was expecting something amazing. In case you're wondering, yes, I think there are books out there that live up to the hype. For me, this is not one of them. 
 The Characters & Points Of View 
 Celaena - I am sorry, but for me, Celaena is not just a strong female protagonist. She is a Mary Sue. Pretty, plays the piano, reads, fights, "one of the boys" but girly at the same time ("when she was free . . . she could buy all the clothes she wanted"), has more than one love interest (and it's not even a subtle reference). What are her flaws? What makes Celaena feel real and genuine? And please, do not tell me she had a terrible past, because it only reinforces the fact that she doesn't have specific flaws! I am not "hating on" Celaena, this is "indifference" - because hate is actually good, it means the characters make you feel something. I feel nothing for Celaena. Where's this character's depth? 
 Ok, it's great that she has all those enemies and there's all that conflict going on - Cool! Because, of course, she's "perfect" (and I mean it). So you really, really have to drug her or summon demons or I-don't-know, but it has to be something out of her control, because otherwise you don't even have a real chance against her "skills". 
 And speaking of skills, less telling and more showing: Apparently, she has got some amazing skills, being the "best" assassin and all, but even if these are mentioned many times throughout the book, they are rarely (or never) shown. Most of the time, she doesn't even act like an assassin. 
 Another reason why I think I haven't connected that much with the character was due to unnecessary points of view. Do not get me wrong, I love other character's points of view when they are relevant, but in this case I didn't see the need for that. Why do we need Kaltain's POV? Wouldn't it be much more interesting that we'd discover Kaltain's plans through Celaena's eyes? Why do we need to know how Chaol or Dorian feel about her? Wouldn't it be more interesting to be left wondering? I feel it would make a big difference for me if this book only had Celaena's POV and no one's else. Plus, it's pretty obvious that she is the main character and everything revolves around her. It's not like a High Fantasy story with focus on many different characters and nations. So, really, why do we need other character's POVs? To reinforce the fact that everything revolves around her? 
 The love triangle (I am not even considering this a spoiler because it's obvious from the very beginning) is not only predictable but shallow (I know, it's YA and all, but still). That last bit in the end, when she 'gives up' one of her love interests? My thoughts were: Ok, she's disregarding this guy so she can have a taste of the other one. 
 And the worst of it all? It's that this love triangle & peculiar romance didn't feel as a sub plot but rather the main focus of the book. No wonder I was so excited when other stuff started actually happening. 
 I actually thought that Kaltain and Nehemia were more interesting characters. Their backstories could have been developed into interesting sub plots should they have been explored properly. 
 The Plot 
 Apart from a few twists, I thought the plot was pretty basic and predictable. This could be related to the fact that Celaena is "perfect" and I couldn't consider the possibility that she could be in real danger, at any point in the story. 
 The "almost" sub-plots: the King, the duke, Kaltain, Nehemia, all had potential. I wanted to see more scheming, more betrayal, more action. Probably this is all going to happen in the next book and I will feel sorry for not giving this series another chance but, well, this is officially Volume 1, it's the same chance that every other series have. 
 The Writing Style 
 Even if the writing style contributes for an easy read and a good pace (let's start with the positive), there were several things about it that I disliked. 
 Positive: short and sweet, overall style is faithful to the tone of the characters' POV: young, informal. 
 Disliked: 
 First, the author has the (bad) habit of describing emotions by describing people's eyes. "eyes shone with amusement", "eyes held mere curiosity", "glimmer of amusement in his eyes", "pity in his eyes" and other emotions like: anger, disgust, pain. All in their eyes. I wish I had this ability to know how people feel by simply looking into their eyes. I know what she wanted to imply but it was a bit too much, in my opinion. When these emotions couldn't be read in the character's eyes, we would have descriptions such as "amusement gone", "anger bubbled" 
 And worse when all these emotions, several times, are about other characters, not the character's POV: "disappointed, the soldiers returned to their meals". This and other type of sentences such as "She had lied, and Chaol knew it" mess up the POVs and make the character feel omniscient. 
 Dialogue tags, the author refused to keep them to the basics ('he said', 'she said') so we have many others and, most of the time, followed by an adverb with no purpose. Action tags between dialogue were not great either. 
 There's a lot of inner monologue, and I feel most of the information is revealed through inner monologue by using different character's POVs. 
 Apart from that, there's also some "info dump" in form of dialogue. 
 Transitions in time were awkward, sometimes even abrupt. "A few minutes passed" and nothing else between scenes, for example. And speaking of abrupt, the romantic climax was abrupt and uninteresting too. 
 These transitions can be also connected to vagueness. The most obvious example was here: 
 "And then Perrington smiled, and finally told her everything. When Perrington finished . . ." 
 Everything, really? Everything what? Ok, you know, we know, but the character doesn't. 
 You probably think I am being picky, but it's a best-selling book we are talking about! 
 Note: As always, all of this is only my opinion and it reflects my personal reading experience.