Oh and of the two brands we use regularly I prefer the avent. The tommie tippee ones can be a little tricky to get the lid on straight and sometimes leak as a result
I also use tommee tippee closer to nature and avent bottles. I've also heard good things about como tomo but haven't tried them yet. We tried the nuk ones with the oddly shaped nipple that says it's just like how the mom's nipple gets shaped within baby's mouth, but she didn't like them as well and there was more mess.