Its true that for the most part that PG delivers the best flavor however, .... I have found that flavorants that have a perfumey tone to them come out much better in the flavor dept when mixed with VG ... also, VG creates a creamier, smoother tone to flavors which I found really compliment flavors such as Vanillas and Caramels.
I've used a 80/20, 70/30 and 60/40 ratio to mix my juices and for the most part I am starting to prefer the higher VG ratios .. the only potential downfall with higher VG ratios is the much slower absorption rate with poly fill cartos .. But very, very nice if you direct drip!