I've got one of these things. I'd call it sort of useful. Cargo capacity is a bit lacking, compared to a regular wheelbarrow. The lift arms are sort of a joke to me, just not enough capacity to matter. The main instance I find them useful is when moving large potted plants with the pot belt. No fighting the greenery when you're lifting the pot from the side.
My favorite use for it is when doing remodeling. It's the right size to cart things in and out of a standard doorway, rather than loading and fighting bins or bags.