I didnt go back and read through the thread, but I dont think anyone implied that it will slow splits down.
It will however slow the cyclic rate down, which as Latech said, can definitely change the feel of the gun. It can also change the way you see the sights. The cyclic rate will always be much faster than you can actually pull the trigger, but the way a gun FEELS to an individual can certainly have an affect on their splits.
Its a pure preference thing. No way to know if you'll benefit from it without shooting a few hundred rounds through one.
Ok point being I like the way it feels