i just finished reading the three books and agree with most comments here.
i love books and movies for two entirely different reasons and want to see the movie as (like someone else said) it 'looks' good. i decided i might read the books first before viewing though and the subject interested me. i will say i am very much an adult but like the odd younger read.
i really enjoyed the first book, an easy simple read with a good basic concept. i read it in one afternoon surprising myself. so i purchased the second in eagerness but it took me almost two weeks to read it as i just couldn't get into it. finally i read the third book which was a quicker read, but partly so i could just get it over with. i did get teary at the end of the 3rd book (i'm a horrid softie and cry at nearly anything
) but overall found it quite average. it felt badly written and edited (like too many scriptwriters on a movie and too much cutting in the editing room) and seemed like it would jump forward in spits and spurts rather than a smooth arc like the first book.
anyway i still found it intriguing but it lacked in fulfilment. i guess partly what it was is that a good book will let me flesh out the characters and places in my head and while i mostly got this with the 1st book i just couldn't keep it up with book 2 and 3 and characters ended up being meaningless and faceless and didn't give me any scope to get thoroughly invested. (obviously i was invested a little from the first book to still get teary at the ending but a lot of newer characters i didn't care less about).