I have used three different bottle for my 3 month old son now. He gets horrible gas and avent bottles are supposed to help with that, but for me they dont. ALso they leak all the time. The only good thing about them is that unlike the plytex bottles i use now, the avent bottles have several stages of nippples so there is always one that is the perfect speed for your baby. Personally i have had more luck with the playtex ventaire bottles and the playtex nursers. They allow less air to get in babys belly, but they only 2 nipple stages, fast and slow. Its good to register for several differnt bottles and let your baby decide which ones are right for them!