Hi,
I've never used store brand formula, not because I think it's worse than the name brands, but DS was so gassy when I first started him on milk-based formula (Similac), that when I finally switched him to a brand name soy-based formula (Isomil, because our pediatrician gave me a sample) and it reduced his fussyness I wasn't going to mess with that. I am sure that all formulas, whether store brand or name-brand have to meet a certain standard. Also, I am not sure whether for us store brand would have been cheaper, since we kept getting the $5 off coupons from the company, AND bought our formula at a warehouse store (BJ's) where the price was cheaper. HTH