From the starter kit you get the following flavors. Sour Cherry, Strawberry Shortcake, Kiwi-Strawberry, Peach Mango, FaZeberry, Green Apple, Fruit Punch.
By far and away Green Apple shit all over every other flavor I tried, even Rainbow Sherbert. It wasn't even close. The problem with most of them is they didn't set themselves apart from each other enough, like they used the same flavor for each red berry regardless of what it actually was. Kiwi-Strawberry, FaZeberry, Fruit Punch were basically the same thing. Sour Cherry was good, but after about halfway through you're sick of the sour taste. Strawberry Shortcake was good but others are simply better. You could make a case for Peach Mango but it just wasn't my style, I could see others really liking it.
After my tubs run out I'll be ordering Green Apple exclusively and using carbonated water, it makes a really big difference in flavor. I'd also like to try coconut but you can only get like a 15 pack of those. See below for my rank experience thus far.
1. Green Apple
2. Rainbow Sherbert
3. Strawberry Shortcake
4. Peach Mango
5. FaZeberry (From here down you could put them in any order because they were basically the same, aside from Sour Cherry pulling up the rear).
6. Fruit Punch
7. Kiwi Strawberry
8. Sour Cherry