VG is made from vegetables which is very thick, especially under low temperature. PG and PG400 are soft ones which are easy to refill and vapor. PG400 can vapor longer than VG and PG with the same quantity. So the price is higher. But PG400 creates little vapor.
Advantages and Disadvantages:
Although VG is thick but it will not leak from the cartridges after refilling. PG and PG400 are easy to leaking, expecially in tank system. So, if you are using tank system currently, you'd better choose VG+PG or VG+PG400 base. It will be better than just using PG or PG400.VG is hard to refill if you are using a syring or a needle bottle. You have to use a big needle bottle to refill. If you are not using tank system cart, do not order VG base.
Which is best for me?
You may be allergic to PG base. So, make sure of this before you ordering any PG related products. If you are using a tank system cigarette. You should choose VG, VG+PG or VG +PG400 base liquid. If you are using a traditional cartridge with cotton inside, you'd better choose VG+PG,VG+PG400 base which are easy to refill.