I'm a Zero Effect fan, but there's some concern that there may not be enough slide travel with the Guardian to use it in its current form...

I was talking with Mark Land about this (Muzzy's lead tech guy, and the guy you see on the DVD...) and he doesn't think it's going to be a problem right now, but we're waiting for someone to try it on the bow. I've got an extra MZE just waiting for my Guardian to get here...