The Kineton or Jobey noseband has a reputation for being harsh.
It gained this by being refered to as a Last Hope noseband - that which was used when all other options had been exausted, on tearaway horses.
As with all pieces of tack from a $5 leadrope to a $10,000 harness if it is not understood or used incorrectly then the person using it needs to re-educate themselves .
A horse should, if handled and trained properly, never get to the point of having to need a Kineton.
Another noseband that I have only ever made one of is a Beucephalus .