This bottle is fantastic. I have had to bottle feed my baby since she was 2 weeks old due to tongue and lip ties. I have also had to feed her formula exclusively because of not producing milk. I have tried multiple bottles: Playtex, Kiinde, Mam, Chico, Nuk, and more importantly Dr. Brown's. Out of all of these Dr. Brown's was the best, but definitely still not great. My baby was still in pain and uncomfortable after eating, and I wanted something better. After further researching anti-colic bottles I came across Natursutten bottles, and they have changed everything. My baby still has to burp, but she does not get the painful gas that would last several hours. Her reflux has improved, and she is much more calm and happy after eating. I am not using the nipples it comes with because my baby can't handle faster flow, even the slow ones are too fast for her. She will be able to use them in a few months, though. For now she uses Dr. Brown's nipples, and they work well even with the anti colic valve. I'm so thankful to this company for designing a product that is so simple and much more efficient at reducing air intake during bottle feeding. Also, not having as many complicated parts to wash is a nice perk. They are also durable, I have dropped them in my stainless steel sink a few times on top of each other and they didn't even chip. I don't do that often and have changed how I wash them in the sink because they are glass and glass is breakable, no matter how well it is made. That said, these are definitely worth the price, and as far as I am concerned the best anti-colic bottles money can buy. I now use Natursutten bottles exclusively and will never go back to other brands. If your bottle fed baby struggles with feeding and has difficulty with gas, reflux, etc., please consider these for your little one. I have had so many problems with other bottles causing intense discomfort and pain for my baby, and these have improved her comfort and enjoyment of feeds by 90-99%.