I used these bags for my small stash after exclusively pumping. They worked well, as expected. I like that the place where you write the date and whatnot isn't on the storage part of the bag, that it's on the zip-lock side.
I don't think the measurements of how much liquid is in the bag is very accurate, so don't rely on that.
My tip is to put the bag in the freezer laying flat and then have a shoe box or similar in there to stack them all. I started off just placing them in the freezer standing up and then had this mountain of balls of frozen milk! Not easy to store