There is no established load limit on the CETMA....Lane was talking about 400lbs was the max hauled so far, but he can't afford to destroy a bike just to see what it could haul. I suspect I would never haul more than 300lbs. But the CETMA can take that in one square shape whereas if you loaded even 150lbs on just one side of a BD you'd have some fun trying to pedal it in a straight line!
Also keep in mind it's not simply a matter do how much weight you can carry that determines a cargo bike's capabilities, but how you carry your cargo, ease of loading and ease of riding.