Limette - I found both amazingly compelling resulting in my current case of Twilight fever. That being said I certainly understand that all appreciation is in the eye of the beholder. Reading romantic fantasy with a critical eye, certainly pulls one out of the moment.
The only statement of yours that I'm confused by is this
"Considering how big the book is I'm really surprised that they made such a muck of the movie."
It seems to me that the longer the book, the more likely they are to make a muck of the movie! Movies are limited by time, usually two hours. In books understanding someone's motives is simple but putting that on screen can be quite tricky. I loved the movie Twilight but I don't think that it's near as good as the book. The only movies that I thought were as good as their books were
To Kill a Mockingbird - - relatively short novel
Pride and Prejudice -- 6 hour movie!
Shawshank Redemption -- short story
I don't think that the movie was a great piece of film, but I did find it thoroughly enjoyable. I just felt the need to defend it, I'm not upset. (Now going off to sit at the Twilight geek table