I have never owned one, but I have seen many use them and like them very much, I think the Yuba is a very well thought out design, do you have a link to the specific model you are considering?
looks pretty solid to me, I am a fan of mid-drive systems in general, and the Curry Electro Drive looks to be very promising, but I have no personal experience with them, just know a shop that has sold Curry bikes for a long time and has had good experiences with them.
The bike is a demo at crazy Lenny e bikes in Madison wisconsin. Looks like a great kid hauler that I would use to haul around my grandson. Thanks for your thoughts.
I have a Yuba Mundo V4 and it is great.. the weight is something you notice when repairing the bike and trying to pump up the back wheel can be a bit of a hassle if you have those plastic side guards, though besides that its a awesome bike..
I demoe'd the spicy curry at interbike this year. I really was impressed with it, along with all the mid drives I rode that day. Cargo bike and mid drive is a really good combination, unless your desires are for a lot more speed than 1000w will do for a heavily loaded bike.