I would definitely breast feed my kids. Why use anything else and pay for it when your very own body supplies it? (Just for one baby, a decent sized can of formula powder is 25 dollars, and we don't have a large income in our house so it's a struggle) It's just natural. Plus, with all of the cleaning you'd have to do with a child around (I don't have a child, but have a neglectful sister who leaves her child with me very often), it would be easier not to have to sterilize bottles all of the time and rush to mix formula whenever the baby gets hungry. It just seems so much more convenient. And again, it's natural!
If my breasts produced formula I would still breastfeed my kids. It is such a perfect way to express love to your child. Breastfeeding releases oxytocin which is the hormone related to love and orgasm and joy. Also, just saying, breast-fed kids aren't actually smart-ER and don't actually have high-ER IQs: This is the baseline!!! We should think of it like this, instead: Formula-fed kids have LOWER IQs!