Sorry to make a wise-ass remark and then disappear for the weekend, but family was over to celebrate my impending birthday (yay...).
My major complaints against the sanjiegun are that until you master it, you're as likely to induce GBH in yourself as others. Mind you, its just Faith's style, flashy and impressive and I can see her choosing it long before she's ready to use it in a RL melee. The other problem is that, unlike a western flail, its a completely wooden weapon (except for the chains) without the mass needed to easily crack bones. I have seen a sanjiegun used with a pinning/breaking maneuver that was just brutal but for that you need to be in kissing distance of your opponent. For zombie crowd control, I'd want a staff. Not great at breaking bones, but you can keep pushing your foes away and a 2 handed blow to the head will induce naptime even thru an SCA-approved helmet.