it's all about just knowing when to use it, kind of like "the force". It's hard to explain really, but I use it most of the time, just for general player movement, but especially for receiving through balls and even some regular passes.
Just start experimenting in situations that currently frustrate you, then start using it at times youy previously might not have thought about it. It's superb for turning defenders when receiving passes.
I think its a stupid excuse for not letting us control are players properley anyway and it doesnt always work, ive played passes to a player who has basically jogged really retarded away from the ball even after tapping super cancel and trying to point him in the right direction.
I always use it to defend, when the oponent got strikers like henry runnin at ur bak 4 i always use square for a computer controlled player to go and pressure him while i control my furthest bak defender to act as a sweeper. its also good in attack when your striker is tightly marked- pass up to him and super cancel towards the ball so he gets there 1st. try super cancelling before you shoot also, you get hell of a shot out of it!
I find its great for two things.
1. A pass to a winger, as the ball is about to go into the wingers path, move him across onto the ball before it gets to its destination. This will put you in space across the defender, allowing you to either turn back and trick him or continue inside and have a shot/pass.
2.I use it to win longs balls onto my forwards, use it to make your player bump into your opponent as there about to head it. Some times its a foul but most of the time, you just knock em off balance and steal the ball. muahahahaha