We are very happy with the bottles. In our opinion, the colic actually been a little more bearable after we have switched from Avent Naturnah and Avent Anti Colic / Classic on this. We noticed in any case, that our baby swallows less air while drinking and then not so often had to burp (big selling point, because this is often anverdaute milk with high come with us and we had to go back to move).
Really great is that you can sterilize the bottles within a short time in the micro. Unfortunately had bad luck with two sterilizers (diff. Manufacturer), where after a few weeks of use, lacked polish. With the MAM products to these devices saves completely!
All bottles are sealed by the way and not drip (my biggest concern, because here was pointed out even at negative reviews). Mixed I see it, that you can not put in a bottle warmer (as in the bottom valve yes holes). This is what we worked around by we are flasks with warm / hot and cold water ready - so therefore saves power that would have been used for the bottle warmer and quicker than doing it would only in these places by far. I found the first still annoying (it was used by Avent that easily folds), I think it's gotten so much better.
Conclusion: strong buy recommendation!