I've ridden most of the big common cargo-bikes for work at various points, though the one I'm still keen to try out is a reise and muller.
BULLIT I'm sure I'm probably going to repeat what others have said on here. There's a reason that all of the delivery companies exclusively use Bullit's. They're big, solid reliable and handle well. As a wee note: there was a geometry change when they moved to the ones with the integrated headtubes out front. The old ones ride nicely, but the newer ones ride even better. The steering feels much more neutral at slow speed tight turns. The older ones started to kick and jackknife the front wheel in really tight slow turns.
8-freights handling remarkably doesn't change when going from loaded to unloaded. It really surprised me, I think it's the straight fork and low wheelflop. Unfortunately, it goes from riding like ass with a really really vague steering feel to riding like ass with a really vague steering feel. I'm sure it's something you could get used to, but unless you have a massive hardon for mike burrows you're probably best to get something else.
Urban Arrow. AVOID! The riding position is so reclined that you can't get any power into the pedals. This means you're relying on the motor all of the time and essentially using your pedalling as a throttle. If that motor ever cuts out you're stuffed. They're also super heavy, super expensive and universally hated by all of th ebike mechanics who have to suffer servicing the things.
Omniums. The cargo and minimax are super super rad. Probably the best cross between a cargobike and a standard bike out there. Probably not suitable for transporting two children and shopping however. The only downside is the same downside as all other cargobikes, which is the size of them.
Christiania. AVOID! rode down the arthurs seat road (steep long road in edinburgh) with cars passing super close, trying to slow down but every time I did the bike would violently try to swing into the kerb. The twin front disc brakes (one on each wheel) are a pig to balance and always end up with one brake being the only one operating. They're also hell when you hit any sort of rough surface.
The absolute worst cargobike I have ever ridden is an MSC Truck it seems like someone had commissioned a bunch without ever having ridden the thing. It wouldn't go aroudn a corner, when it was loaded up the flex along the length of the bike was extreme, you would start turning a corner and there would be a lag as the weight behind you twisted the whole bike. The bike would hit it's max twist as you hit the apex. Hideous hideous thing! Thank god we offloaded that dross to Edinburgh. ;)
I've also ridden a bunch of modified pedicabs, trikes, cycletrucks etc. but none of these are suitable.