We bought these bottles to go with a Medela breast pump and have found the extra 3 bottles to be excellent and very useful. We will pump into a bottle and then store directly in the fridge. We tend to use all expressed milk within a few days (so don't need to freeze it), so the bottles work out far easier than the storage bags. They are easy to use and sterilise, and also they fit easily into a cup of warm water, which is useful for warming milk.
We tried using the teat on these bottles and our little guy does not take it - we have to transfer the milk into another bottle for a feed, but we don't find this an inconvenience.