It really depends on what area of history you want to do. If you're interested in the ancient world outside Greece and Rome, you have no choice but to go to Macquarie. Macquarie history, both modern and ancient, is pretty awesome, and based on the few classes I had to take at Sydney, is honestly comparable with Sydney. If you want to do archaeological fieldwork, Macquarie easily wins hands-down due to the number and quality of activities, and support of students going there.
However, if you're generally interested in history and don't really have a specific passion, I wouldn't decide based on what the universities offer but more on things like transport and whether you like the campus. Do you like anything outside of history? Do you want to maybe play a sport or something? These questions are very relevant and should be considered.
if you are looking to do ancient history I would seriously consider Macquarie University. They have the largest ancient history department and offer a wide variety of ancient history courses from the classics stuff like Rome/Greece and also Egypt etc as well as a broad range of ancient languages. They also offer a Bachelor of Ancient History (Hons) in contrast to just a Bachelor of Arts.
In contrast, USYD doesn't have many ancient subjects on offer (about 2-4 a semester) and they only teach Rome/Greece (ie. what is generally termed classics). There is nothing on Egypt etc. The same with languages (only offer Latin/Ancient Greek). So realistically, USYD is quite limited, in that it will give you only a classical ancient history education, and you will end up repeatedly doing courses on the Roman Republic (I've done about 3 now all called various things/in various guises but still covering the same period!).
That's essentially right, but you've missed the real issue, imo: Not that Sydney doesn't offer a wider variety of ancient world subjects, but why that's the case. Sydney essentially teaches you Classics or archaeology, whereas Macquarie teaches ancient history. If you want to learn decontextualised textual sources, Sydney's great, really. Otherwise you need to have contact with scholars who are active archaeologically.
Edit: Oops, something that also warrants mention is that, say you end up enrolling in MQ or USyd (for argument's sake) and you think the other university would be better for you, you can easily consider transferring.