It's such a tough call. Really I'd have to lean you towards NW just because they sell the
batteries that are tried and true and if you decide to return it, it will be because you just didn't like it, not because the battery was faulty. That and because they are close to you, which is a nice thing to support.
Vapor Girl offers her own version of echo style
batteries with a long cutoff. Los Marauder has the most current version (military style-she calls them) and he reported liking it. You may want to bug him on his profile and see if he'll update us on how he's doing with it. In the beginning they were a little buggy but I think that's all worked out. The reason she doesn't get a lot of press is we tend to stick with the Hangsen originals.
But there are more and more batteries coming out with echo threading so this will become the spot to discuss those too, I'm sure.