On the one hand, yuck. (Understatement!)
On the other, to misquote Jagger and Richards, "Who killed Nick Berg? / When after all / It was you and me". If the government of my country hadn't backed the US government, there wouldn't have been an invasion, and he'd still be alive. (That's not to take away the direct responsibility from the people who do such things.)
The yuck was very definitely winning, up until today, with the publication of articles like this one on the curious features of the video.
As reported (but not shown) on UK news, the video was simple: he said who he was, and then someone immediately cut his head off, followed by a rant to camera. Single take, no question of it being faked.
It seems that's not the case. If there's any editing (the extremely unfortunate jargon is 'cut', from the days of physically cutting film) in a piece, it is extremely likely that it didn't happen in real time. Minutes, hours or days can pass between one shot and another.
(Michael Moore was guilty of this at the end of Bowling for Columbine.)
So... I'm more tempted to see it, in order to see what editing was done and to see if it does look as if it was faked.