Simple, which frontman/era of hard rock legends AC/DC do you like more? Personally, I love Bon Scott, but have mad respect for him and Johnson both. But I feel Bon ultimately had a better stage presence and an unfaltering charisma about him. Not to mention his lyrical prowess. I overall enjoy the scope of work with Bon much more than that of Johnson, as well.
Bon Scott, saw them in 1978, a few months before Highway To Hell came out ! The Scorpions was the opening act, AC/DC was the second band and Ted Nugent last, my ears were ringing for days !!!