There hasn't been any real change in the triggers. There's a stigma attached to Kahrs related to the old NYPD trigger that seems to follow the kahr brand around. In reality the trigger isn't all that bad even on the NYPD guns, a bit longer travel and a bit heavier.
Doubtful you'd encounter that in any of the guns you mention. Certainly not a deal breaker even if it were.
All things being relatively equal I tend to lean towards new versus used as well but at the same time you know what you want and if used can get you some of those things at a doable price that's not a bad thing either.
Might start on a plus's and minus's list, pro's and con's.
In Memory of Paul "Dietrich" Stines.
Dad: Say something nice to your cousin Shirley
Dietrich: For a fat girl you sure don't sweat much.
Cue sound of Head slap.
RIP Muggsy & TMan
"If you are a warrior legally authorized to carry a weapon and you step outside without that weapon, then you become a sheep, pretending that JOCKO will not come today."