Stephen King has always been one of my favourite authors, but admittedly his stories can be very hard to put to screen. It's just the way he writes and the things he can write about.
But this movie captured it superbly. Incredibly moving, but gritty in classic King fashion. I've even read the book and comparing the two, it's still an excellent adaptation.
I would highly reccomend this movie, even to those who are not familiar with Stephen King or his books.
Duncan does an excellent portrayal as John Coffey, and plays the role with grace and respect.
And any fans of Tom Hanks will adore his riveting performance as well. Aces on all sides, great casting.
Book or movie, I will usually suggest the book first, but in this case, you can pick up either one first and still be satisfied with the other.