I haven't yet read Maas's Throne of Glass series, though I have all four full novels on my shelf. I can see why her books are popular - her prose is easy and fluid, and the narration was, for the most part, entertaining and well-written. 
 The first half is dedicated to Feyre's inculcation into the Spring Court and her budding romance with Tamlin. I did not mind the relationship; I thought it had an interesting start, and I thought though Tamlin is a bit bland, his dedication is evident when they fall in love. One annoyance with his characterization is how much he growls. He's not unsociable, but he tends to growl more than he talks. He has a beast form, and he is a natural shape-shifter, but there is something about a male character that growls to communicate that annoys me a lot. 
 The other characters are infinitely more likable, from Lucien, who is a smug, smarmy silver-tongued snake, whose friendship, especially in the latter half of the book, is at times more compelling than Tamlin's love, as well as the infamous Rhysand, who is the most complex character in the entire book (besides Nesta - a weird part of me is shipping those two HARD because it would be extremely entertaining). Feyre is neither memorable nor super-annoying, but just an average modern teen (is it teen?) fantasy heroine. She has a backbone, but snaps more than she speaks, which I personally find annoying. It seems every heroine has to be super chock full of sassiness and wit, but a lot of that devolves into whining and anger. She's rough with her sisters and father - who are admittedly unbearable and selfish, at least in the first glimpse we get of them - but fails to voice her true issues with them. And what is with the angry banter? I understand why teasingly mean banter, you know, insulting with a gleam in your eye, can be fun, but what guy (or person, really) responds well to someone who barks insults at them? Because Feyre doesn't strike me as the type to have enough subtlety to discern between insulting and light mocking. 
 The fantasy element was interesting, though perhaps not as established as I would like. Feyre encounters a few "dark" creatures and "evil" faeries, as well as other High Fae and (low?) fae. We get some backstory as to how the kingdoms were divided, the state of faerie/human relationships some five centuries ago, and the events in the Northern part of the continent, leading up to the "blight," but it takes a while for events to be revealed. 
 Her focus on color and light was also a welcome addition. It also made for a stark contrast from Feyre's feelings as to her new home (where, as she grows to like the Spring Court, she sees everything in terms of how she would paint it) to her experience Under the Mountain, where she does not dare to utilize that perspective at all. 
 Which brings me to two major issues I had with this book. First, Feyre's reaction to the true events of the "blight." Of course, Feyre lurves Tamlin, so she would forgive him any slights or, you know, betrayals to her trust. However, something of that magnitude, (view spoiler)[that he essentially lured her to his court, lied to her about why she was there, and proceeded to get her to fall in love with him, would have any normal girl questioning whether that love was real in the first place. Yes, I understand that he explains later on that he gave up on that attempt rather quickly, after his first awkward attempt at flattery, but wouldn't a normal cursed prince (HA) question his motives for falling in love with the girl who was to break his curse? Perhaps to compensate for having her fall in love with him? (hide spoiler)] 
 The revelation also took FOREVER to occur. We see Feyre having a grand old time after her initial discomfort and clumsy attempts to return home. She hears snippets of interesting, though meaningless, conversation regarding some scary lady who's terrorizing the countryside. We finally find out Tamlin's secret a good 60% into the book - and not even from Tamlin. In fact, Tamlin is naught but a statute who snogs her once for the latter 40% of the book - not really his fault, but still, compared with Rhys's interactions, it's hard to muster up care for Tamlin, besides a general sense of "Oh, I hope he doesn't die, but I am not going to worry all that much since it's impossible that he will die because of lurve." 
 Oh, I guess this was three issues, not two? Whatever. The third issue is Feyre's disdain for humans after returning from the Spring Court to her humble human family. This is a major issue I have for any book that features super-human characters because, inevitably, the protagonist, who is always human him or herself, begins to hypocritically detest those lowly human bugs in favor of the supernatural creatures he or she has come to expect. Feyre practically vomits looking at her old lover Isaac and wonders how she ever gave him the time of day when she could entwine her limbs with Tamlin. This I find hugely problematic. It smacks of racism. I get being charmed by the lush environment and beautiful people of the Spring Court and being disappointed in your new environment in a homesick manner, but turning that around and finding your own kind less worthy due to their inferior physical appearance? This made me hate Feyre with a passion, and it was hard to recover from that hate enough to even care for her trials in the latter half of the book. (view spoiler)[I suppose it was good she became a High Fae in the end, because how could she otherwise stand to look at herself in the mirror? (hide spoiler)] 
 Because of that last issue, I will likely not be continuing this series. (What more is there to want anyway? There were no plot ties left untangled, save Feyre's promise to Rhysand.)