I had tried Coke Zero when it first came out last year or so, and thought it was horrific.
However I've had it again recently (today, last week) and don't think it's that bad. How can that be?
At Target on Friday night, we spotted an endcap filled with two new, odd beverages: Diet Pepsi Jazz Strawberries and Creme, and Diet Pepsi Jazz Black Cherry French Vanilla. In the interest of solid web content, I tried the latter. Plus it was 79 cents.
The flavor is, well, very artificial: Diet Pepsi with cherry, really, with just a smidge of that faux canned vanilla flavor dialed in. It's definitely not something I would go out of my way for, and even then I'd probably just choose water.
It also reminded me a lot of Diet Dr Pepper, honestly - so why reinvent the wheel? And why "Jazz"? I wonder if they're going after the same oxymoronic demographic (!) that the Utah Jazz go after.
So, in summary, you can skip it.