I'd get the uncut version...
If you haven't seen it, maybe you should watch it before you buy it. It's definitely not for everyone as it contains pretty offensive material.
But if you are like me, and aren't offended easily then you'll probably love it. It's brilliantly filmed and cut and the music is fantastic. it's also incredibly realistic.. (and thought provoking, depending how deep you read into it)..
make sure you get an edition with the 'making of' doco on it...