Used K&N filter of some previous stock street bikes and didn't notice a difference in behaviour, nor was I looking for one. The motivation was the potential of long term cost-of-maintenance reduction, and possibly filter performance insurance.
That said, I have noticed the air filter on the CB during my tours has stayed remarkably clean. This was definitely not the case on previous models in the same riding region. Therefore, I am not motivated to change to K&N on the CB.
