Cannibal Holocaust is better
I just acquired Jungle Holocaust and I must say that it is pretty good. However, I bought the Grindhouse version of Cannibal Holocaust a month or so before I purchased JH and I must say that CH is much better. CH has a much better story, it is shot better, and it has a greater feeling of depravity and despair. I loved how in CH that the documentary filmmakers got there just desserts and in some senses it taught us something about ourselves. CH was much more gruesome which only served to prove its point. JH, while I enjoyed it very much, just seemed to be a traditional survial/horror film. JH does teach us certain lessons but the impact of CH was much stronger IMO.
You should never ever doubt that which no one is sure about.