Changes flavor how? Stronger flavor or weaker?
PG produces less vapor, but retains flavor better and provides a better
throat hit. VG is sweeter and provides much more vapor but IMO less flavor. Less flavor can be good if it matches your taste buds. I'm
vaping some Cignot VG USA Mix in 26mg right now that I like much better than even their PG version. The VG produces clouds of vapor with less throat hit and a smoother and milder Marlboro taste. Some would like it and others would say that the TH is weak. To me it's (right now) the best representation of a real cig I've found yet. My wife likes the SEC Kent VG and hates the throat hit of PG mixes. She says they are too strong for an ultra light smoker.
Juices are individual choices. If you go by my review, you may or may not agree and I might not like your favorite choice. It's a shame that we all have bottles of
juice that were recommended by others that we hate. I guess that is why there's a trader forum here.