Knowing which vendors you are getting the juice from would probably help narrow down the choices.
Yeah, I hesitated to mention them because their Root Beers are highly rated (and exactly the same) and, being a huge fan of both, I hate to spoil their hard earned customer bases. But, you know, eff it, for the sake of openness I get my Root Beer juice from Backwoods Brew and Madvapes (besides, the flavoring is probably cheaper from Madvapes than straight from the source since that's what they do - move mass quantities at good prices). The only difference I can tell between the two is that you pay $16.50 for 30ml from BWB and $12 for 50ml from Madvapes. Madvapes does sell the flavoring for less than $2/10ml, but I want to know where it comes from since if for some reason I ever didn't have it (state ban or something) I would want a back up DIY source because vaping anything else for long and all I would do is sit there and crave this instead.
It's the perfect juice for me: it's simple (obviously only one flavoring) and clean (flavor is clear), my cartos last longer with this juice than any other I've tried (literally hundreds over the years), the flavor is complex enough to stay interesting (even though there's conveniently only one flavor ingredient), the TH is perfect for me even at 6mg (a lung TH instead of a throat TH, but not irritating like other some that flare up my latent asthma), and I just plain can't think of a juice that hit this many right notes for me. I NEVER thought I'd be a one flavor vaper...and now I am, mostly.
And it doesn't hurt that I'm a Root Beer fanatic/connoisseur anyway, so I had a predisposition to like it if it really tasted like Root Beer...and it does.