We bought these Born Free bottles based on advice from my sister-in-law about trying to get bottles which are free from Bisphenol-A (perhaps hormone disrupting). Normally I am not too concerned about things like this and hope for the best in terms of keeping my baby (now a one-year-old!)safe and healthy, keeping in mind that people have been raising children for thousands of years and weren't ever too worried about the impact of chemicals, etc. Anyway, our Tommee Tippee bottles which we'd used for months were a bit tired and our son was starting nursery so we needed some extras, so I went with these.
They are really good, for a couple of reasons in addition to being free of the chemical: first, they are better for a baby who prefers to be more upright when drinking out of the bottle, because of the shape and length of the teat. With the Tommee Tippee bottles our son had to practically be horizontal to get the last bits of milk out. The Born Free also seem to flow very well with its air vent. We bought level 3 teats as our son was 11 months when we started using them and a voracious drinker. Overall we've been really happy with the Born Free bottles and I would buy them again.