I always prefer a 6 pack.
With a 3 pack, I'd use one broadhead for experimentation on a target. That would leave me 2 broadheads for an actual bowhunt.
That works great if I'm bowhunting from the house, but if I'm on a 3 day package bowhunt 500 miles from my home out in the far west or south Texas boonies, I want more than 2 shootable sharp broadheads in my quiver.
Also, with a 6 pack, on a long trip, I want one 6 pack package to take with me. With a 3 pack, I'd have to carry two, 3 packs. Knowing me, if I lose or misplace one 3 pack, I'm down to the lone remaining 3 pack.
I like the old adage. "Better to have it and not need it, than to need it and not have it". :D