Buried deep in the comments on one of the pages on the Starbucks vegan frappuccino was a petulant whine wondering why the company used soy milk at all when almond milk is so obviously superior.
You like what you like. Pay no attention to the man behind the curtain.
Geri Maria Harris, on the Houston Press blogs, did a somewhat more sophisticated comparison of one brand each of almond milk and soy milk, testing them to see which worked in what recipes.
The good news is: for people eschewing cow's milk in favor of plant sources of milk, both almond and soy milk were great alternatives. We recommend going with the Almond Milk for breakfast foods, baking sweets, and if you're really looking for a good doppelganger for cow's milk. For savory cooking and baking, go with the soy stuff.