Listen to what Bri has to say and you'll not go far wrong.
Rangefinding needs to be done using every possible method at your disposal. Then you need to play the odds based on the information discerned from using all of the different methods. Relying on one method alone is a recipe for disaster. Once upon a time, and occasionally at some less well informed clubs, bracketing could be remarkably reliable. As clubs/coursebuilders have got wise to bracketing it's use has become less important.
Chances are these days that I've already half decided (to within 2-5 yards) what range a target is before I even take my rifle out of its bag. Doesn't stop me using a bracketing chart even if it's often just for show!