I’m just trying to see if it’s just me who has a real issue with these bottles for leaking, and then when the vent system is removed the nipple collapses or if it’s just my experience. My baby prefers Dr. Brown’s because of the narrow nipple. All other brands that have a “narrower” nipple are still too wide or the shape is irregular or they collapse as well. It’s been a struggle because in the beginning she didn’t have a strong preference until I started pace-feeding and the narrow nipples are preferred for that method, and now we can’t go back it seems.