Hmm, I've probably had more mediocre than good or bad, but there have definitely been some that have set my gag reflex off.
#1. Vapor Bomb--Birthday Cake
Almost certainly the worst juice I've ever tried. Really disappointed, because this was right in the middle of my "vaping food is awesome" stage and what sounds better than birthday cake flavor?! Well, it was horrible and possibly the only juice I ever threw away as opposed to selling or just keeping as a backup.
#2. Vapor 4 Life--Wow Cola
Another rancid flavor. This one seemed okay for the first few minutes, and then my stomach just started to turn. Really chemical-y taste. The weird thing is, once I noticed it in this one, then all of my V4L juice was ruined. Then again, that's like dropping a slice of cheap bologna on the floor and saying bologna is forever ruined. No great loss.
#3. Freedom Smoke USA--Nutella
Got this as a sample and nearly vomited. I've never tried real Nutella, but I can say with 100% certainty that it doesn't taste like that, or no one would buy it.