Today I was screwing around in training with it.. The horizontal knockback is great against some characters, it is a nice approach against some projectile spammers..
It does some weird *** stuff to your momentum. As mentioned before by others, there is some wird thing that allows you to instantly reverse your movement. I think it involves double jumping right before, as that was the only way I was able to nearly reproduce that effect on purpose.
I think it has great potential as an edgeguard, especially by short-hopping, turning around, and hitting people into the side of the stage. there is no upwards knockback, as well, which is important in brawl.