I tend to agree with Whiskers on this one. I've shot a lot of whitetails with them but I don't think I would attempt a bear?
Rage recently came out with the new Extreme 2.3 model that boasts the new metal break away "collar" instead of a rubber band to support the blades. They work very nice and gave me new confidence in shooting them last season. The deer I killed with them thought differently though! LOL!