jlh is the only one that has been to both USYD and Mac.
I would think, that the COMMERCE degree at Mac is less flexible in terms of majoring, but more flexible in terms of transfering/changing your major.
I would recommend the Comm-Accg program, plus, you get the best lecturer for 1st year accting, the president of CPA NSW (subjective i know )
i can't speak about the e+b faculty at usyd so i wasn't keen on answering... but here goes:
as griz mentioned already, commerce majors at USYD are much more flexible in that you are able to choose what you want to do a double major.... all you have to do is just fulfill a certain number of credit points per area in commerce...
when looking at courses also think about accessibility to the uni and stuff like that .if you live near macq and want to work near macq or something it may be a better choice. it is the whole package that you shud decide on. but the usyd courses do sound good in that they are flexible and what ever