The PG tends to dry you out- dont be scared- it sounds worse than it is... but a higher PG mix will dry your mouth and lips some- drinking water helps resolve this... it comes down to finding the balance that works for you... the higher the VG, the less dry issues you will have but also the thicker and less sweet the juice will be.
For me, my first experience with an ecig was Blu... when I used them I would get a very heavy feeling in my chest, almost like someone was sitting on it... come to find out that Blu uses 100% VG juice. I have since gone to custom liquids from HHV at 15mg and 70:30, I find the 70:30 to be nearly perfect- great flavor, no heavy chest...
I can testify to that to; not concerning Blu but concerning 100%VG (straight glycerin from the Pharmacy); I tried vaping that for a SHORT while; and yup "a very heavy feeling in my chest" is exactly what I found.