I have a Yuba Mundo. It is a long tail, rides like a regular bicycle, and is a fantastic cargo bike for big loads. I got it because I wanted to haul both of my kids and cargo simultaneously, and it excels at that. It doesn't sound like you would need nor want something that big and beefy. Yuba makes a smaller cargo bike, the Boda Boda, that will fit on most regular bus bike racks since the frame is designed to allow the front wheel to turn 180 degrees and therefore shorten the wheelbase.

I have commuted a fair bit on the Mundo. While it is not my first choice of my bikes to use for my commute unless the loads are huge, it scoots along just fine. If I was you, I would make sure I couldn't get away with more of a regular bike frame and racks/panniers for my needs before looking at something more specialized like a cargo bike. One big thing a cargo bike has over a trailer though is that you never need to worry about getting the trailer out and connecting it. The bike always has the cargo capacity no matter where you are or what comes up at the last minute.