The biggest difference of the top of my head is that a 5 Years trained teacher will have a higher minimum salary than a 4 year trained teacher. Other factors that might influence your decision would be the ambience and quality of the uni/subject. If you just want to be a math teacher, then the USYD has a good mathematics faculty from both the faculty of science and the faculty of education and social work.
Picking either USYD or UNSW doesnt really affect your job opportunities.
I can't really comment on the course at UNSW because I havent seen what they do over there.