I love my Yuba Mundo. It has been more useful than I expected it would be. Shopping is a breeze and I no longer have to pass on those bulk discounts or car-oriented larger products. Towing a bike has been a much more regular use of the Yuba than I anticipated and is a good way to pick up friends from the city centre. Carrying people is also fun and surprisingly easy, providing you do not mind going a bit slower than usual and I expect that people with children will find riding with them on the back quite easy.
The longest heavy duty ride I have done was to IKEA in Ashton. IKEA is one of those places which is designed around the car-culture and I was pleasantly surprised to find bike parking (Although it had no road access). I bought a pair of Billy bookcases and added them to my two pannier bags of supplies making a load in excess of 50 kg. The ride home was surprisingly enjoyable, the bike handled well under load, the uphills were manageable and the downhills were incredible. I think I got from Ashton centre to Manchester Piccadilly station in around 15 minutes.
I have done a fairly long (50 km) ride on the Yuba with a lighter load, to Oldham and then Rochdale and then back along the Rochdale canal. It is quite crap between Failsworth and Manchester so we took the road for that section, but the rest of the route is enjoyable, even as far as Hebden Bridge and beyond.
The most unexpected ability the Yuba has is to grant the owner a kind of infamy. I have been asked by acquaintances, co-workers and even completely random people if I am the guy with the giant orange bike. It is quite cool in a way but hopefully the effect will die off if the cargo bike concept catches on with a few more people.