I think the issue of ease of mixing is completely overstated. Up to this point in time I've gone with 100% VG. After I've broken a liter down into smaller bottles, all I do to get it ready for mixing is take one of the 120ml amber glass bottles out of the freezer, rotate for 1-2 minutes under cold water at the sink (which serves both to mix it for nic hot spots and warms it up enough that it's less viscous), and then open the bottle at my mixing table a stir a couple rotations with the dripper. Never experienced any hot spots this way, and by the time I've measured and poured in my flavorings, the nic is ready and very easily gets measured out into my 30ml or 60ml syringe. In my experience it's a breeze to work with.
On the other hand, with my last liter purchase, and from here on out, I'll only be buying in 100% PG. I've read that PG is better for long term storage of nic. PG degrades less quickly than VG (we're talking after 1 or more like 2 years of storage). And nic in PG oxidizes less quickly than in VG, since the higher viscosity of VG allows little air bubbles to hang around in the liquid for longer. With the vaping apocalypse upon us, I'm trying to do everything I can to ensure that the nic I'm stocking up on lasts as long as possible, and it seems like using 100% PG is one thing I can control that can help in that regard.