Pepper spray will only piss off a grizzly! Given the choice of a 44 hand gun or pepper spray you damn sure better pick the 44.
Pepper spray will work, unless the bear is really pissed off or otherwise highly motivated. Then its just extra flavoring.
I don't think it will piss them off, but they may charge through it. I've never actually used it, but from folk who have, I'm told the probablility is it will work. But not the only option you want with you.
You should have both, but the big spray gun works pretty well.
Aside from Dirty Harry, there ain’t a whole lotta people can hit a charging Grizz with a .44, especially a head shot, which is what it will take to down one of those suckers.
Stun ‘em with the spray, then open fire.
Better yet, bring a bear rifle.