I have used a 6x by 42 mm Leupold for a long time.Mine has no PA or target knobs,just a standard duplex.Unless they made a change,that duplex is one mil,like the mil-dot,from center to the tip of the heavier crosshair.That is useful for range estimation and some Kentucky windage.
The 42 mm lense provides a 7 mm exit pupil,which means about as good of low light performance as you will get.
The 6x by 36 is an FX2,iirc,and the 6x by 42 mm is the FX3 series.iirc,better lense coating.
I am thinking about getting another one.
I rate them very high.