Brains are generally surface imperfection only and are always slightly smaller in diameter than a regular BB, so there is little to no chance for it to mess up your feedpath or gun. I just got the two from Spawn28 and one of them is about 40% brainy and the other one has some dark streaks and is borderline brain - I'm honoring both of them with free bags of course but neither one of these would damage a gun - if you shot 5000 of them all at once? Yeah, you'd probably chop a little and need to clean your gun, but, it would have to be seriously brainy (80% all around perhaps) and they happen so rarely there is little chance of that.
Congrats to Spawn28.
Brain BBs are pretty much unique I think due to BB Bastards manufacturing process. I've never heard of any other brand having them.