The dry wall anchors are easy to break as others pointed out, but they are usable. The key is to drill a large enough hole, and use manual screwdriver to screw the drywall anchor slowly.
Another difficulty is to drill accurate holes make the bracket balance. The effective way I did is to first hold the bracket against the wall and make it balanced, then use the largest size drill bit that can pass through the screw hole to manually drill a shallow hole, purpose is to locate the center of the screw hole, then remove the bracket and drill the hole use the same drill bit, note to hole the drill perpendicular to the wall. The use the larger drill bit to drill the hole, finally screw in the dry wall anchor. Finally install the bracket with 4 screws. I use manual screwdriver. That's it.
Clark G 
