all basic formula is essentially the same. the only real variations are soy based formula, formula for really gassy baby's (like Enfamil gentlease) but each brand has the same ones. like similac and Enfamil both have soy based formula, and a formula for gassy babies. but there's really no major differences between brands.

are you transitioning to formula? I don't know that any of them are substitutes for breast milk exactly