I ordered a new one from Power Brake Exchange in San Jose, who also rebuilt my OEM booster and swears against Chinese junk, but the one I received came in an unmarked box. It appears to be high enough quality, is working great, and isn't leaking all over like the original.
If you get one that eventually begins failing, it will take less time to simply replace than you will spend lording over the minutiae of is this original or not. Ultimately, this isn't a McLaren F1 we're talking about, and it's clamping down with the crudest of disc brakes that I've ever seen.