I have used the Ursack every since their inception in Yosemite, Sequoia, Kings Canyon, and the Northeast, many years now.
I stealth camp, that is never cook and sleep in same spot. I wash daily. I don't use ANYTHING scented. I boil water, and rehydrate organic vegetarian food with less odors than fish, frying meats etc. I use the odor bags, and if treated with respect, that is inside a silnylon bag of their own, I find no problems. I have never had a bear show interest in my camp in 15 years of being there.
All that said, I can see that for a number of backpackers, they may not make the grade. Bears are lazy, they will hang with those places of easy food. The folks who frequent these places leave food out and about and big odors with cooking, their clothes have allot of scent as do their bodies and tolietries, etc. They may not secure the bag and they may not know how to chase off a bear successfully and ethically.
This summer is a big experiment, I fear the worst but pray for the best.