I might add a quality called earthiness. Rootbeer is a combo of fetid swamp mud flavors counterbalanced with cloying yucky sweet. It doesn't really make sense to rate one as right and the other off; it is an issue of balance where both can be weak, medium, or strong... as long as they match. Well, you could add a quality called strength.
I mix rootbeer about daily using zaterain (sp?) extract and agave syrup poured into a half liter carbed water. The extract is in a funny shaped bottle that tends to surge out, so I often accidentally create what I call "black tar rootbeer". Then I have to really cram in agave syrup or else it will be disgusting. Or too much syrup and it becomes candy-like kid stuff.
Other issues fall way, way down the scale. Who the heck cares what color it is... but with my extract, a medium strength gives a color of liquid and foam is a wonderful slightly translucent glowing happy color. Black coffee color, and the strength will be harsh. Light color, and the strength won't be strong enough to overcome a certain seltzer bitterness.
Ok, since you will mix your own extract you can break it down a bit more. I would downrate anything with peppermint or licorice taste because I hate them, although often used as a substitute for that cancer related ingredient. But it's hard to rate components because like I said things can be adjusted. More carb can give bite that the extract may lack. Oh, there is the quality of sudsiness, which is absent in most other types of sodas which don't like to retain foam.
