Unfortunately all three weakened near the connector within a few months to the point where they only intermittently charge. Really disappointing.
I'd venture to say those aren't real Ankers. The ones I have are built like tanks. I personally abuse some of my lightning cables, pulling on them, stuffing in bags in a rush, etc. They've lasted years and look new.
Note: I do buy the ones that come with nylon, not sure if that makes a difference.