When I first tried Coke Zero, I found it better than Diet Coke, and closer in flavor to regular Coke. For me, Diet Coke has that strange Nutrasweet after-taste, which I have never liked.
I didn't find that with Coke Zero when I first tried it, seeking something that was nominally "zero-calorie" without having the bad aftertaste I associated with "diet" beverages (and other foods for that matter).
Now, though, when I drink a regular Coke (or worse, a Pepsi), I find it extremely overly sweet. I can still drink other "regular" colas, but they're not my go-to beverage choices any longer.
I do wonder how Jolt Cola would taste to me now; probably absolutely vile or something (I've also found that Grape Crush - which was already ultra-sweet - is almost unbearable to drink from a sweetness perspective).
This doesn't happen to me with any other diet drinks, not sure why this one isn't "consistent"- I guess maybe because Diet Pepsi I have more often from fountains instead of containers, since it's usually a backup when a restaurant has no other diet options