The way I look at it there are only 3 options. 12 ga. pump shotgun, pepper sprayor nothing at all.
Based on what I've read the preferrable shot placement is a brain the size of a pop can. Factor into that formula a bouncing moving target and a large amount of excitement. If hiting the brain is the only viable option of stopping the griz than using a hand gun is out. (I'm figuring most of us are not great shots with a hand gun).
If pepper spray only works under the best conditions (e.g. mountain winds) this may be a better option than the hand gun but not the best option.
The option I'm leaning toward is the pump shotgun with either 00 buck or slugs. Probably the 00 buck in the chamberfollowed by another 00 and thanseveral slugs. At 20, 30, or 40 yards I know I could get a lot closer at hitting that pop canevery time with the shotgun over the hand gun. I think I also could get back on target quicker after the previous shot with the shotgun.The first shot will be in the air to scare off the bear.
If there are several of us hunting together and if my friend gets attacked I don't want to be shooting using the 00 buck or the hand gun nor do I want my friend shooting at the bear, if withina few feet of me, with the 00 or hand gun. If someone is hit with a bulletthey could be in worse shape than a mauling. Remember we're probably a few hours from help.
The draw back to carrying the shotgun is the size but a sling would help nicely with that.
The other thing to consider is if you're hunting with another person or two maybe more people would help stop a charge and expecially if more than one person is shooting.
I believe Winchester makes a nice pump (name excapes me at the moment) for about $300.
Let's hope we'll never have to find out which option is best.