Flavor 39 is really close to Boba's Bounty, I'd buy it again.
I'm actually going to buy some black and mild flavoring to try create a recipe that's close, and perhaps that flavoring might be good as a stand-alone.
As for another
juice close to Boba's, I'd go with
El Kamino.
(
@Doorknob beat me to it)
Another good one that's not as sweet is
Casablanca.