Folk/Viking/Pagan metal is an incredibly nebulous genre anyway. It's hard for me to believe that Falkenbach and Draugnim play the same genre of music as Finntroll and Korpiklaani.
And when did popularity come into the argument? Just because a band hasn't been recognized by the general public doesn't mean they don't play good music.
Burping/gurgling vocals:
http://www.youtube.com/watch?v=_WLPvzGgWs0
No one ever said popularity was a measure of good music but there is a line to be drawn when something like what you just posted comes into an argument.
WHO THE FUCK LISTENS TO THAT? Is what a lot of people will say in utter disbelief and when you can answer with only "well.. it's popular here and here"
It doesn't really hold much weight. And man that is fucking awful (whatever you posted)