Premium for ME is about the flavor experience. It's about loading up a bottle on my REO and sitting back and enjoying the flavor the way it was intended, not artificially, candied versions of fruits, for example. Real, extracted flavors of the original fruit. It's not difficult to figure out who I think does "premium" flavors best. Last count I have tried over 100 of their flavors and I think I could count on one hand the number out of that 100 that I just went "yeah...no" on the flavor. Not that the flavor was bad, I could tell it was well crafted, it just wasn't a flavor that worked for me.
I try different vendors and always go back to my primary vendor, because the flavors are so much more pure tasting (to me) than other vendors. I still try other vendors from time to time, because I really don't want to put all my eggs in one basket. But it's a tough act to follow for sure!