Gerber Nuk bottles are gerat! I was experimenting with bottles when i found out my 3 month old had Acid Reflux. Turns out this bottle nearly stopped all the spit up due to its air system. The only concern I have with this bottle is that when I shake the formula before i feed my son a little formula does leak out of the bottle at the top where the hole for the air system is. Also it is a bit wide. It's wider than most other bottles so it doesn't fit in some diaper bag pockets. Because it's so wide, it's a little harder wash with a bottle brush. I have to clean it a little longer than other bottles...