I love this formula! My little guy is 12 days old now and this is what they started him on as soon as he was born in the hospital and he had no problems. We tried to switch it up once we got home with a competitors brand, that was a bit cheaper but it seemed to upset his little belly, so we went back to the Similac and no more belly problems. The only reason I give it 4 out of 5 stars is I think they should put more of the nipples in the boxes, you only get one per box. We also have the powder Similac formula, but I admit I am spoiled with these ready to feed versions. It makes life so much easier and I am able to feed my son in a more timely manner with these little bottles, I will definitely recommend these to all new Momma's out there!