These Legendairy Milk barrier bags protect your milk and don't leak! Here's a closer leak at these bags.
These bags have a barrier on the inside that is supposed to help preserve milk freshness with a UV barrier and something that blocks oxidation. I can't speak to how well that works but I gotta say these seem a lot less likely to leak than any other disposable bag I've seen.
It has a little spout thing that you can cut off to pour in a bottle after you've thawed (though be careful make sure you have it centered on the bottle, was a little hard to see)
One thing that surprised me about these bags was that they lay pretty flat when you put milk in them. In my experience most bags that can stand up on their own are bottom heavy when lying flat.
When you're ready to use your frozen milk, there is an easy pour spout that you can cut off and then pour into your bottle.
1) Lays flat 2) The barrier means it's unlikely to leak, and it may be more effective at protecting milk 3) Stands up on its own 4) Has an easy pour spout
Overall pros: