If you're looking for a critical review, you will not find such here. Here, praise is all that will be spoken... I suggest you search elsewhere for the angry reviews. 
 Shall we move on? 
 First and foremost, the elephant in the room. In every book, Artemis changes... just a little bit, maybe, because of those he knows in the Lower Elements. It's obvious how this book takes that slow growth, and very slowly gives you signs of his growing sentimentality. A whisper of sympathy here, a hiss of guilt there... nothing big, we all expect that after reading the previous books, I assume, correct? What is completely unexpected is the sacrifice he eventually makes to save all the people he must have completely vexed in his entire life. This, I think, is the final compensation. 
 Holly Short, the other protagonist of ours, is of course also very important. The bond she had somehow managed to forge between Artemis and herself was... immensely solid. The fact that he originally kidnapped her... and somehow they end up being the dearest of friends... is quite the lesson to humankind. Forgive thy enemy. Her love for him is incredible, and I am separate from the crowd that demands they become a couple, because I feel like that's enough. 
 Butler. I can't even... describe the pains Butler goes through to keep that boy safe and alive. He must love the Fowl family more than anything, because that man is devoted. He nearly died, more than once or twice, to save him. And he would do so again, if it meant that any of the Fowls (primarily Artemis the Second, as he is the only one to put himself in such situations) were in danger and could be saved. 
 I would also like to dedicate a simple praise to Foaly, who loves his wife to a degree unconceivable to us filthy Mud People. I would also like to mention that I did enjoy that short chapter in which Cabelline was in the spot-light. 
 I loved Harry Potter. I wasn't the age to 'grow up with the books' as Harry Potter came out; no, I just devoured them when I was 12 and moved on. But with Artemis Fowl... I could actually grow up with them, and that, I suppose, is why I'm so completely smitten with them. I read the first, second, third, fourth, fifth, and sixth book at random places in my constant stream of books between the ages of 12 and 14. Upon hearing of the seventh book's release, I was all over it. I am 15 at the point in which Artemis is 15 (Sort of). And it was similarly so in the other books as well. I was with an age of the boy in question. That did a lot to boost my love of the books. 
 In summary, I couldn't ever put them down. And so as my advice to you, dear reader of this review: it is, indeed, worth it. 
 Also, in case you have read the book: 
 (view spoiler)[So, Holly is the narrator all along. The last book ends as the first begins, so naturally, Holly must have been the one telling us of events the entire series. Who would have known? Of course, there are points at which she couldn't possibly be narrating (as some things are not being spoken aloud) but I imagine that a very large portion of the books is merely Holly explaining to Artemis their past. (hide spoiler)] 
 5 stars; that's from my childhood.