Something that I always hated with the KeyDown and KeyHit, was that if you use them in multiple scripts, they can give back different results since they could have been used in a different script. I think I had similar problems with mouse Hit as well, but I am not sure.
So for instance you have two scripts, both check for the space bar hit. Script 1 says that the spacebar has been hit, but script 2 says it has not been hit. That is because Leadwerks sets a 'hasBeenHit' flag to false once you have requested it in script 1.