there are some things which may not be that good and the uni can work on, but overall I have loved my experience at uni.
ANU is very unique that it is rather diverse with most people not even from Canberra.
Living on campus is also an amazing experience to be so close to uni & meet so many people
Teaching quality - I guess some specific courses aren't taught well? Or maybe even some schools. I've quite enjoyed my experiences studying most of my courses with the School of Politics & IR. I've heard good things about many schools/colleges at ANU - the arts & science ones tend to do well. Law and CBE (business/economics) are probably around the same as other unis (in terms of teaching quality)
only real downsides is that food on campus & stuff is kinda expensive that's all :/
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however, there are obviously many factors which can factor into your decision.
living away can be expensive, so it might not be worth it if you cannot afford it and just save money living at home/going to a local uni