I have seen several YA films over the years, so I have some context for thinking about this one. I have /not/ read the book; this is based solely on watching the movie.
This provides an interesting situation, an evil adult, and some adventurous kids. It also portrays a decaying city, built to last 200 years, but clearly running down because it is older than that.
The problem is that I have seen this sort of thing done better many other times, and so (I suspect) have you.
And not just in YA films: /THX 1138/ and /Logan's Run/ are not all /that/ different, albeit made for an older audience.
So maybe that's part of the problem: although a YA film certainly must be made to entertain teenagers, most of the ones I have seen work for adults as well (some, to be sure, better than others), and this one doesn't work for adults very well.
But, if you are a fan of the book or it looks attractive to you, by all means see it.