I picked up two tons of gravel in it today and the fella in the merchants was pretty impressed with it too. Mogs have a real fan base with folk who know what they are don't they.
It's the first time I've carried a load on it and I was surprised at how it pulls. I found it rather strange that it isn't really any slower?! Still not at all quick, but it felt much better knowing that it didn't really notice the weight on the back.