I purchased a bunch of the Avent baby bottles before my daughter was born.  They are pretty pricey, but they are supposed to be some of the "higher quality" bottle on the market.  However, I found them to be less than adequate.  They worked okay for a while, but after a few uses, even after being very careful not to "over tighten" the caps, they begin to leak.  I ended up just buying some cheap bottles that worked better than the Avent bottle systems.  I don't think anyone would reccommend these bottles to anyone they knew.  The only pros to the bottles are the different sizes they come in,...