I like EOTechs best in terms of their "user experience", and I think they work best on ARs. I prefer Kobras or Aimpoint H-1/T-1 Micros for AKs. If you use the highly desireable UltiMak gas tube rail to mount an optic on your Kalashnikov-pattern long gun, make sure it can stand the intense heat, Aimpoints are thermally robust (and so are the Kobras with the Weaver rail mount, I'm told, although the batteries may not be), but these have been reports of problems with EOTechs on AKs getting cooked after heavy fire.