I found this U.S. Fish and Wildlife Service article interesting:
http://www.fws.gov/mountain-prairie/species/mammals/grizzly/bear%20spray.pdf

Another aritcle I read said this:

"A handgun or rifle seems like the obvious choice but according to studies when a bear is shot there is a high chance it will become enraged and further its attack if not taken down with the first shot. In fact when relying on your firearm there are quite a few things that could go wrong. Your gun may jam and malfunction, you might miss your target or the bullets may strike the bear but merely injure and enrage it. Even if shot multiple times."

"Just to clarify bear mace isn't the same as regular pepper spray it is much stronger. Regular sprays are designed to incapacitate humans whereas bear mace was specifically developed to repel an enraged bear."