What jtlewis said is correct. Also, I have learned that basically what device you are using helps determine what
juice is best for it. For example, since a high VG juice is thicker they can clog clearomizers and cartomizers easily. If you like to use tanks with cartomizers, you are better off using a higher PG/VG ratio (something like 80/20 PG/VG, or 70/30) so they wick good. The same with clearomizers but you can get away with more VG juice with them than tanks with cartomizers. If you drip on atomizers, pretty much they all work good but heavy VG can gunk up the coil a little faster, but if you like a certain VG juice alot, it's worth it so no worries. Also, I used to think I didn't like VG but once I got some awesome juice from Clouds of Vapor, I love it now. And they somehow dilute it (maybe with drinking alcohol) to get around the thickness of it so it vapes well anyways. If you are going to use a cartomizer without a tank and put your juice in it, then you can get away with using a thicker VG juice in it. It's really a personal preference, as you can see, depending on the flavor a person likes and what type of device he/she wants to use it in. And not every 100% VG juice is the same as another 100% VG juice. There are alot of variables. I hope I haven't confused you too much. It takes trying out stuff to find your sweet spot on whatever device you are liking to use.