Terrifyingly real
I've been to Haiti several times and this film captures it well. The culture, the poverty, the corruption are all depicted in S&R to a tee. I also believe the story of the man who re-emerged in the 1980's after dying in 1962. He was walking around with his death certificate in hand. Wade Davis wrote the book after hearing of this.
The Haitian culture, voodoo, sorcery and the rituals for disposing of (and possibly reviving) the dead are not something easily understood. I doubt its something science will ever be able to explain.