I watched Ralph Bakshi's early animated version of Tolkien's saga with my son, who's on a Tolkien binge, having watched Peter Jackson's film twice (or even thrice!). I could see he wasn't thrilled, but he managed through. Maybe he was interested in the differences between the versions.
I'm not sure whether I was, since I found Bakshi's film boring, clumsy and pretentious. I'd seen it before (on big screen), but the film proved to be duller than I remembered. I don't really know what one gets out of it, if one hasn't read Tolkien's book (or seen Jackson's version!), since Bakshi's film is lacking in good, solid narration. I don't know whether anyone seeing the film will care much for the faith of the Ring or the characters.
I promised my son I would try to seek the unofficial Bass-Rankin sequel to Bakshi's film, but Lord help from finding it!
More Overlooked Movies here at Todd Mason's blog.