It's been almost a week since I started using these. I ordered 4 of them. 2 to save and marry in a dual 18650 mod that I'm building and the other two to rotate in my mechs. One of them significantly outperforms the 35A Efest (I only have one of these to compare to) and the other is just a tad less than equal. I don't have any fancy scientific equipment to test them on, just my experience with them.
Using them on the same mod with the same atty that has not been rebuilt. One appears to have much less internal resistance because I can use it down to 3.7v before I notice any drop in flavour or vapor production and the other starts to lack around 3.9v to 4v. I have also observed that they like to rest longer in between chain vaping for best performance than some of the others.