I'm tasting Zevia's Natural Cola for the first time as I write this. I actually ended up finding it at the local Whole Foods and they had a few other flavors. The only other flavor I can remember is root beer.
One thing you will notice when you look at the ingredients list is that Zevia contains more erythritol than stevia (2nd ingredient versus the 5th ingredient). It also contains 45 mg of caffefine from coffee.
As for the taste, I am not impressed. It does not have as much of a cola flavor as I would like. There's a little bit there, but it is a bit too subtle for me.
I might try root beer or one of the other flavors, but I would not have much of an expectation from it, and I would have to find it at a good price - while it was on sale at Whole Foods, the normal price comes close to $1.00 a can.