I absolutely love these bottles. She took to them immediately. She started using them at about month old. They are honestly quite heavy but I don't mind because I wanted something that wasn't plastic and that would work while I was still breastfeeding. The nipples are said to have a close flow to the way breastfeeding feels for baby. I can also vouch for their durability because I've dropped two of them. Both times the bottles were fine I checked them for cracks or fractures, but they were still solid. I do want to say I dropped them on carpet, so I can't say they would survive if you hit tile, but there is always a chance. I recommend the starter kit which comes with three 4oz bottles and two 8oz bottles. It also comes with a set of Avent Soothies Pacifiers, which I also would recommend. The only problem I had was the lids. Sometimes if you aren't careful when putting on the lid, the threads won't connect properly. Then you shake the bottle, and suddenly you...