I use it but like the others I tend to use it sparingly during the early season. Go here to listen to the aggressive Rattling wav.during the rut. This is when they are really getting into fighting. If you use rattling in the early season, you have to try and imagine the dear are just sparring or "Playing". It is a much lighter rattle. Never slam the racks together at this time but more place the antlers together and just gently rock them back and forth. At this time the bucks can still be traveling in bachelor groups. So any stray buck may come to investigate the new sounds. Good Luck!
http://www.wideworldofhunting.com/soundsofwhitetail/WhitetailDeerSounds.htm
Eric S. Stacy AKA DeerDope