and be sure you note that the guy that is riding on the "mud video is actually riding in a waterhole. the bike wouldh ave mad it though those holes with ease withought duals.
I think for certain things they help, however try to go down some tight trails and they are useless. The added tire cost alone is enough to make me not want them.
I have a smallmouth stream that has some great fishing. But wading and swimimg is the only way to get from hole to hole. Water depth is from 6in to over 6ft I was thinking I could Float down stream stoping at the good spots until I got to the next road cut. I have also been looking at those floating 6x6's but they are really high.
the 6x6's are really rough riding too, I wasn't impressed with one my friend bought it cost him 10,000 new with all the stuff and he can't sell it close to what he has in it.
your still gonna be top heavy so instead of a cool lookin four wheeler floating in 6 foot of water you'll just see the bottoms of eight tires just above the surface of the water!