Yes, they are both regarded as safe. One is not more safe than the other, but on rare occasion a person may find that they have an adverse reaction to one or the other (never both, as far as I've seen) including rash, sore
throat and similar symptoms.
PG will provide better
throat hit and clarity of flavor.
VG will provide more clouds or vapor but may mute the flavor of the
juice.
Lots of people mix them together (usually 80%PG and 20%VG)
It's just up to your preference.