Oh, boy!
Here we go again! Interesting article; it may be that everything we've been told about bear spray vs firearms is wrong and based on a very flawed reading of very flawed studies. It appears that bear spray is very effective at 'hazing' bears that are curious but has about a 33% chance of dissuading and actual attack. And it's less effective against black bears than Grizzlies.
I would encourage everyone to carefully read the linked article, then read it again.
Discuss!