Ah, I can see you are ready to punch through the screen again: yes, another standard to learn, another few more thousand to be trained and certified, another series of debates about what method to use...
Well, it may end up being not half that bad. Word from the streets in Geneva is that ISO 21500 is going to - shock! horror! - incorporate the best of both. Prince2 and PM-BOK are pretty outstanding systems in their own right, even if their approaches and emphasis do differ quite a bit. I for one would welcome a defining way to marry them both off and produce a beautiful new ISO baby, with the best bits of both parents found in it. And if you know both the current standards, ISO21500 should not be a new horror, but a familiar and logical approach to doing things. And hopefully, it won't end up as inbred as a Balkan village...
We can only hope...and wait.