I have both of these scopes i much prefer the mark 4 but thats mostly due to the turrets , most say that there is no difference in the internal just the turrets are different and i dont know if there is or not for sure but the mark 4 clicks feel more positive and they take a little more effort to turn which i like, as for the glass i am not really a fan of leupy glass i buy them for the warranty and repeatable clicks, i have elite scopes that are noticably clearer than the leupys and they happen to track as well....im getting off topic here.......buy the mark 4