I know not of this peg you speak of, but its really personal preference.
my opinion:
VG produces more vapor, but the
throat hit and the flavor isn't as strong as it is on straight pg
PG tends to bring out the flavor and give a bit more of a
throat hit than VG but the vapor isn't going to be as dense.
some (very few) people find pure pg to be a little harsh or have small allergic reactions to it.
Most juices are a PG/VG mix, which I prefer.
edit: I agree with 80/20 mix being good.