It doesn't matter what uni you go to, but as others have pointed out, it's how well u go in your course. There is hardly any difference between Usyd and UNSW in terms of commerce and economics in Australia. People think that because the cut-off for commerce at UNSW is higher than Usyd, then this means it is better. This is not true, the UAI's are only based on demand and supply, and how many positions for a particular course are available.
If u were to work in South East asia then possibly a UNSW degree would have an edge over a Usyd one, but then again if u were to work in a country like America, Usyd would have an edge over UNSW.