My impression has been that pastrami and corned beef have a cure in common, but corned beef is simmered whereas pastrami is spice-crusted and smoked.
This seems reasonable, but recently I've been hearing of both foodstuffs cooked entirely sous vide.
Without the cooking method distinction, the only remaining difference is that pastrami now has the crust and liquid smoke. Is liquid smoke sufficient to move into the realm of pastrami? Or is this just pastrami-flavored corned beef?