I LOVED these bottles! This brand is all i used with my son. I wanted a bottle i could go back and forth between breast feeding and bottle feeding and these worked great we never had any nipple confusion. I also used the closer to nature version of these bottles too. They are more aimed at Colic babies. but even these have their nipples made with vents to try and help keep air out. I have 4 kids and with them I have tried many different bottles (ventair, soothies, playtex nursers, breastflow) and these are the only ones I would ever recommend.