I've tried
three Hangsen flavors so far, and I just ordered
three more.
I started out at 2%, which was way too low. I amped it up to 6% and it's better. I think the flavors are great, but the potency of flavor is pretty mild. If you want a strong flavor from them, you'll need at leat 5% or maybe even 10%. Beyond 10%, you're on your own. I rarely use that much flavoring for any brand, unless it's a combination that just grew out of hand!