The flavor carriers are usually PG and VG. VG can mute some flavors, but it doesn't make them wane after a few drips. I do notice that some of my flavors seem to "wane" after dripping it several times. Like I said, it could be due to your taste buds and
sense of smell getting used to it. It could also be the difference between vendors, as you pointed out. Flavor is such a funny thing for people and some might like one vendor
juice while others can't stand it for whatever reason. Not all vendor's are created equal.