We started breastfeeding, and then ended up trying 10 different formulas after that until we had a semi happy baby. We were using a Nutramigen when we went to see a GI specialist. He recommended Gerber good start soothe. We didn't notice a huge difference behavior wise between formulas. We went with the soothe because it was cheaper. Also, the nutramigen had a funny smell to it. Almost like cheese its. The soothe didn't have a funny smell at all.