There are some videos of these in use; they are very effective when used within the chute's operational parameters: when the airplane is at altitude and moving

There are some videos of these in use; they are very effective when used within the chute's operational parameters: when the airplane is at altitude and moving at an appropriate (not too fast) speed, particularly over harsh terrain. However, like all emergency devices, they are not a panacea. They don't protect against one of the most common fatal GA accident scenarios: loss of control at low altitude (base/final turn when landing). In that case, there is not enough time for the parachute to inflate before the airplane hits the ground. I'm all in favor of BRS being available as options and after-market STCs on all small airplanes, but we also need to make sure emergency training isn't reduced to just "pull the chute", since there's a lot that can still go wrong outside of the chute's operational parameters.