Generally I'd say yes, flavor does decrease the higher the vg percentage if the flavoring percentage remains the same. Many vendors juices taste good at any ratio, and I think they adjust the amount of flavor according to the ratio requested. Pg-free juices can still pack a whollop of flavor if the mixer is taking it into account.
Some flavors to me taste better at high vg, and some at high pg. Bakery/desserts, rich, or creamy flavors work well at high vg. The thicker fullness of vg vapor and roundness to the taste it provides are positives for those. I've been really digging creamy fruit vapes at high vg lately. Drink vapes like cappacino, coffee and cream, Chai Latte, and smoothy or yogurt drink flavors also play well at high vg. Vanilla, caramel, maple types work well too.
High pg seems to work better for light fruit flavors, tobaccos, any subtle vape, and maybe candy vapes.
But in the end it's all really personal preference. I often choose around 50/50 when given the choice. A good middle ground that most vapes work well at. I do go for the high vg on creamy vapes and will often choose higher pg for tobaccos.
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