I've heard some people say that seeing this new film would be a waste of time and money, since three other documentaries have already been made about the case (i.e., the "Paradise Lost" trilogy by HBO). Having seen the HBO films myself, I, too, doubted that I would learn anything new from "West of Memphis". I was wrong.
"West of Memphis" shares some new evidence obtained via extensive investigations funded by filmmaker Peter Jackson, a longtime supporter of the West Memphis Three. If you saw the "Paradise Lost" films and were still on the fence regarding the innocence of the West Memphis Three, this new evidence just might convince you.
The new evidence not only excludes the Three (none of the DNA evidence from the crime scene matched any of the three defendants), it just happens to match someone else. Other evidence (albeit hearsay) also appears to implicate this other person. I won't give his name here. See the film and find out for yourself.