"It is a boon having keyless chucks, but the problem lies in the fairly severe motor braking. Releasing the trigger brings the motor to an abrupt stop but the mass of the chuck means it tries to keep going, in a direction that loosens its grip, not all at once, but little by little until the bit drops out. Weirdly this happens more with the 10.8 volt drills. Hex bits last slightly longer, but not much. It is infuriating, but I would rather not go back to keyed chucks when bits have to be constantly changed. "