That is definitely a personal thing. I've actually always felt at least for Canadians, Irish schools had a better reputation because they had higher requirements for Canadians than Aussie schools. For the longest time a 28 MCAT and a 3.4 GPA was all it took to get into USyd and Melb.
Ironically, i've noticed that reputation doesn't go by world rankings in Australia, the best students still get in straight from high school and schools that have gone post-grad only have lost out on the students who are now going to UNSW and UQ since they have undergrad entry programs (I believe), but even that point is really moot because medicine judges almost everything based on licensing rather than reputation like in some other fields.
Backup is important and lifestyle is as well. I'd rather live in Australia lifestyle wise over Ireland, but the flipside is that Ireland is closer which does help with flight costs and travelling back and forth for interviews, electives and research.
In terms of matching to Canada, reputation has almost no correlation. The best match rates in fact according to the stats collected from Ireland by NIMSA in fact come from schools that traditionally in Ireland were not considered the most prestigious. What should matter is how much elective time you get, lifestyle, cost and reputation for teaching and most importantly whether or not they give you a spot for residency as backup.
