Review of Sweet and Tart Flavor-TFA:

I started by adding a few drops to my tank with "blue raspberry jolly rancher" (recipe on reddit), and it tasted exactly like a blue raspberry sweet tart.  I have started making a juice with 1.6% Sweet & Tart and 8% WF Sour Blue Raspberry.
I will definitely be getting more net order.
As for Bullcity itself, this was part of my second order, and just as my first order, everything was quick to get here and as I ordered. I was pleased to see that they have apparently switched to Chubby Gorilla bottles since my first order. Very pleased with this company.