I like the mylar since it seems to have the longest lifespan with nice welded seams. There is a number of places that have bags for sale and we are investigating where will be the best for us to get them from. Aiming for US made as the materials will be a bit better.

I've learned that the vacuum sealing bags are not nearly as durable as the mylar seems to be. We've had the vacuum bags break pretty easily in the freezer.