I used Parent's Choice Infant Formula with Iron Milk Based for all three of my children.  If you compare it to Similac it is very similar nutrition wise. I had no problems with weight gain or being undernourished.  You can not beat the price of this formula compared to the "Name Brands" that are out there.  I would reccomend this formula to all mothers.  There really is no need for expensive formulas, and if you child needs special formula, parents choice has many to choose from, including soy.  I really don't know why anyone would spend more money on a name brand, especially in this economy....