I have a friend who's brother in law used one on a CA backpack trip for the very same reason.
Black Bear found where he stashed the sack and tried to get into it. Bear didn't open the bag, but everything inside was mashed up like if you took a bag of M & M"s and rolled it between your palms.

In his case they yelled and threw rocks and bear ran off. The literature said to tie to solid branch at least 5" in diameter so bear can't gnaw off branch. That was harder than you might think, finding a suitable branch that thick and still low enough to reach from ground and tie that specific knot the want you to use. He also said that branch had been gnawed on to the point if they hadn't chased the bear off, it might of broken and then what do you do, chase the bear thru the woods?

Bottom line they liked the strengths/weight of bag, but next time will bring some strong cord and hang bag from a high limb out from the trunk like in the old days.