1. Sometimes milk leaks if you don't screw the nipple really really tight enough.
2. Originally I use pigeon bottles. When I changed to Avent ones, the milk flows very slowly as compared to pigeon.
3. Avent PES bottles are quite expensive (used to be the most BPA free bottle, but now I think the CHU Chu large feeding bottles are more expensive). I bought them at Jusco BB promotion when there is a discount of 20%.