There are many different opinions about PG and VG eliquid. There are many mainland companies pushing VG over PG and it is mostly due to the fact that the PG juices are cheaper and if they are selling VG, they want everyone to think that VG is better than PG. They are good and bad for their own reasons. A lot of companies pushing the VG make a lot of claims against the PG pertaining to safety. They say the VG is safer. Well, they are equally safe and there is more research/information of vaporized PG than there is on Vaporized VG. For years, we have been breathing Vaporized PG at concerts and in Clubs/Bars, and shows where they use fogging machines. There has never been any health hazards or banning of smoke machines. Vaporized VG is new, so technically there is more research on the safety of PG vice VG.
PG is more runny and adds better flavor to the ejuice. VG is thicker and adds more vapor, but reduces taste and throat hit. So, ideally you want a good mixture of both. The ideal ejuice will contain both PG and VG balanced to provide a great tasting, vapor producing, and throat hitting ejuice.
VG is thicker and will tend to cause the atomizer to heat up quicker and will require more atomizer cleaning. You can expect the life to decrease with VG.
PG is thinner and will tend to leak into the battery easier if over filled, but if you have manual batteries that are sealed then it doesn’t matter other than it will leak over your battery if you over fill it.
PG adds more taste & throat hit – VG adds more vapor.
That is Propylene Glycol and Vegetable glycerin eliquid facts in a nutshell.