These bottles are a bit on the pricey side. My new daughter in law uses these for my 3rd grandson. They seem okay. He's on soy formula, so he doesn't need a lot of air in his tummy. So far, it doesn't seem like they let air in and he seems content.

My son loves these bottle. I like that there are 4 flow levels of nipples for the bottles. Very easy to clean. Great quality. Avent makes great products.

I loved this bottles. Easy to hold, to clean and baby did not get too much air from drinking.
I like that you pick from different stages of nipples and I also had tops that converted the bottle into sippy cups. So you get your dollar's worth for usage.