I read (well, listened) and enjoyed the trilogy (not my favorite ever, but still fun) and the movie looks pretty true to form to be honest. Even some of the voices sound the same as the audiobook. I love when they use the same people or at least keep things unified.
Also, did you get a chance to visit Brandon Sanderson's Twitter Chat?
I got one question in (a really lame one I concede), but there's lots of good stuff in there if you want to check it out. Just go to Brandon's profile to see the whole thing.
Here's my question and answer: