Honestly, neither one. Best bet is to be patient and habitually scour the auction sites and the classifieds here to try and catch a better deal on some factory mags, or bite the bullet and pay the going premium. The difference in performance is worth it for factory.

If you absolutely must buy one of these lesser brands, I would probably go with Promag and swap out the internals for S&W factory parts. I've heard some folks have had success with this, don't know if I'd trust my life to it though.