Electric cargo bikes come in two configurations. The first are front-loading bicycles, also known as bakfiets or Long Johns, which suspend a cargo box between the rider and the front wheel. The other design is a midtail or longtail, which extends the rear of the bike to accommodate more bodies and gear.
Both ways have pros and cons. I’ve found that the older the rider, the more likely they are to want a front-loading bike, which in addition to transporting the kids can be used as a large container for garden equipment, tools, and more. However, you will need a garage or storage space and a very good, reliable locking system; They are more difficult to maneuver and much heavier if you have to go over curbs or rough terrain; and they don’t feel particularly stable at slower speeds.
If you’re a smaller or lighter person, you may prefer a midtail or longtail, which maneuver more like a regular bike. However, the weight is suspended at the rear and higher up, which makes some people nervous about dropping it. I have a longtail; I prefer the maneuverability, but it can be a pain to make sure everything is secured in a rack or saddlebag. If possible, I recommend making an appointment at your local bike shop to try out several models before committing.