The pg nic for longer storage life is not really factual imho... Yeah, pg has a re-test date of 2 years and vg 1 to 1 1/2 years, but firstly, it's not recommended to have working nicotine bottles out in rotation for a full year plus and second, vg nic should last longer in freezer before high oxidation occures.
Also, with vg nic, you have the option of making max-vg mixes with only the pg from the flavoring, which many likes or atleast wants the option to be able to make at a point, whereas no-one really wants a 100% pg mix or i've atleast never heard about such demand.
So to me, vg nic is really the better choise, since it's both more flexible(unless if wanting 100% pg!) and holds longer in freezer
As said allready, the only downside is that it is more annoying to use if mixing by volume, but no problem if mixing by weight though...
Also, if using vg nic with water in, then it can oxidize worse than pg nic...