Recently I've had occasion to buy organic eggnog (I only buy organic, because the "regular" invariably have high fructose corn syrup) from three different producers available in the San Francisco Bay Area: Rockview Farms (Trader Joe's), Organic Valley and Straus.
Tastes in eggnog vary, so I'm not going to try to rate them, just describe them comparatively:
Rockview Farms: the thickest, yellowest of the three, but also the one with the most additives (both starch and carageenen); sugar is the second ingredient. I don't know if the color and texture create an illusion, but it seemed like the eggiest of the three.
Organic Valley: medium thick; sugar is the second ingredient and contains carageenen. Predominant flavor is vanilla, rather than eggs or nutmeg.
Straus: the thinnest, palest of the three, but no additives. Sugar is the third ingredient, and it's noticably less sweet and has a more pure dairy taste than the others. Good, well-balanced nutmeg flavor.
Both the Straus and the Rockview Farms held up well to the addition of a shot of brandy (vbg). I'd happily drink all three of these, so the choice is really whether you like the richer mouthfeel of the versions with thickeners, or the less rich (but also less cloying) Straus.