Pros: they don't have plastiscizers
Cons: they can crack if you drop them when they are frozen
These bags work very well! I have used them for my 14months of breastfeeding my son and continue to use them with breastfeeding my 9 month old baby girl. I put the milk in, get all the air out and freeze them flat. The tab on the end has a place for you to write the date and amount of milk. They do not have any plasticizers that can leach into the milk, but that does make them crack if they get dropped while frozen.