I have used the bags quite a lot and have had no problem with them. I think the real problem is, and i have observed this a coupele of times in the field with others that have a sawyer, is that they squeeze the heck out of the bag. So ya, its gonna fail when you push it past its limits. A steady firm squeeze and rolling the bag up works just fine, and i have been using just the 1 liter bag that has come with it. no problems at all.

and all the people i know that need new bags sat there and put everything they have into squeezing the bags.