In my own testing, FSC556-equipped 14.5 middy is easier to keep on target than 16 inch middy with regular flash hider. As many have noted above, with FSC all rifle movement is recoil, but no muzzle rise. I've not done low-light shooting to comment on flash suppression, but if you're interested in DNTC, I assume it'll be very bright.
As far as noise is concerned, it is very loud. I once was asked by a range officer what kind of beasty caliber my AR was chambered for...