Which is better soy based or cow milk infant formula?

Depends on situation: Some folks prefer the bovine protein as more human like & there is some question whether the soy lives up to its quality. That said, most kids would never have any appreciable difference in growth/development either way.The exception comes if a kid is intolerant to one. If so, the other product or a specialty formula like alumentum would be less likely to cause GI symptoms.