last weekend while at a pistol/carbine training day i had the opportunity to shoot a mag through a glock 21 set up for .45 super. 255 gr hardcast loads at IIRC 1100 fps. recoil was noticeable and a few seemed to think it was a little much, but i really didn't think it was bad, definitely controllable with proper grip. the gun had replacement fiber optic sights and a grip reduction with stippling. the owner built the gun specifically for trail carry here in ID where black bears are always around and the occasional grizzly can be encountered near the divide.
Im sticking to my ruger SBH .44 mag for bears but something like this might be a decent option for someone looking for a semi auto/ higher capacity/ more concealable/ more familiar platform. that said, i almost always have a rifle with me, usually .30-06, and the camp gun for bears is an 870 with full bore slugs.