How does it steer?
A steering linkage runs under the cargo box connecting the fork and handlebars - each of which has its own headset. Steering is tight and smooth, a little twitchy at slow speeds as you start rolling forward from a stop, but once you get going it settles down and doesn't require any special attention to track in straight line. The long wheelbase takes most of the width of a typical residential street for a U turn, a little less with your foot down. The bike makes nice sweeping turns on 90 degree corners and is quick steering enough to get out of the way of cars if you need to. I imagine the shorter cargo bike would have a little tighter turning radius.
Generally, the bike steers better with a kid or some cargo in the box and continues to steer well all the way up to the recommended max cargo weight with as much as 175 lbs up front. I hauled a guy from the office who weighs more than 200 lbs. around a parking lot and there was a little more flex, but no other signs that the bike was beyond its recommended load. As anyone who has done much bike touring will know, 175 lbs. of cargo is a lot to ask of a bike - even the best chrome-moly touring racks will start failing at significantly less than half this weight. I'm impressed with how well the Bakfiets handles really heavy loads - it doesn't feel much different to carry 25 or 150 lbs. on flat ground. Whether or not you can pedal up more than a slight incline with such a load is another matter, but in moderately flat neighborhoods like NE Portland you could easily haul over 100 lbs. around without much effort. I figure a large grocery run for my family with 4 full bags is never much more than 50 lbs. including milk and beverages. A couple of small kids plus groceries is still well under 175 lb.