No it's definitely not.
There are numerous other freight providers that own and control the entire process from pick up to delivery NZ wide other than Mainfreight.
Why as a customer would I use Mainfreight instead of others? They aren't the cheapest. They don't provide a superior product or service. Other competitors are just as big and therefore can pick up/deliver my order just as quick.
I'm finding it hard to uncover what makes them "different" and what their competitive advantage is.