With practice, a double action revolver can be fire as fast as most semiautos. (Not a revolver vs autos statement, by any means. Simply my opinion.)
Five good shots from a revolver should stop anything in your path (six is better, but there's the question of bulk and carrying on a loaded chamber... even with transfer bars... blah, blah.... not trying to start a debate).
HOWEVER, I have been charged by black bears, at less than 100 feet. I can tell you from experience, that I would not have been capable of well placed shots. I was unarmed and alone for all, and scared sh**less for the first one. For the second charge, I still had an incredible adrenaline rush. There is no way I could have held a pistol steady enough to make the shots count. (The third encounter was not a charge; but me wielding a big muddy stick, and throwing it at the bear, to allow me to get to the other side of my truck. A search of my name and "black bear" should turn up some results for a better explanation.)
My choice would be a good, hard cast bullet in the .44 or .357 Mag. Knowing what I do, about my own body and reaction; I would be torn between the wheel gun and a semiauto, though. Having 10-15 rounds, versus 5-7, would be a very tough call to make.
Honestly, the 10mm Auto would win this battle (for me). It's a great cartridge, with good magazine capacities. But, there is a problem: Weight.
The pistols are heavier. The cartridges are heavier. It's a lot of weight to haul around.
My ideal compromise would be a .38 Special or .357 Mag, in a 5 shot snubby. The compact size, combined with performance, would be enough to comfort me against most threats. If 5 shots weren't enough... I guess I should have paid more attention, and avoided the situation.
Knowing what I do now; I will wait for large predators to get closer, before attempting to fire. It's a gamble, but mock charges are fairly common (the only reason I am able to type this), and it adds some probability to shaky shots actually hitting something important.
Five crucial shots are better than fifteen, "I'm over here - leave me alone" shots.
"Such is the strange way that man works -- first he virtually destroys a species and then does everything in his power to restore it."