The admissions is way more straightforward in Canada. If you are one of the top students in your high school (my younger daughter was the top student in her high school) then you almost just pick a university and go there. Again the classes are more in your major and less spread out in other topics. Otherwise I did not notice a difference in terms of the classes. I thought that getting an A was more difficult in Canada, but this does not seem to have applied to my daughter who studied there.
At all of the Canadian universities that we have looked at, freshmen are not required to live on campus. However, on-campus housing is available at least for freshmen who want it. The availability and cost of off campus housing will vary significantly depending upon which university you are attending, which is of course also true in the US.
The drinking age in Canada is either 18 or 19 depending upon where you are. I have been told that this mostly takes the drinking out of the dorm rooms and into the bars, which makes it less of a problem. At least my daughter never reported any problems with other students drinking in the dorms.
My youngest graduated from a university in Canada this past May, and took a temporary job at a COVID vaccination clinic while looking for a permanent job in Canada. She did not find anything (two interviews, no offers) and eventually came home for a visit, and then went to Europe for nearly three months. Then she came home for Christmas and started looking for a job both in Canada and here in the northeast of the US. Apparently the biotech industry is hot here in the US. She had interviews nearly every day and got three job offers in four weeks, and started one (in the US) about a month ago. She is quite happy with the job that she took.
In her case she did not seem to have any trouble finding work in the US. They did interview her quite extensively and I did wonder whether they were trying to figure out how much she had learned since she had attended a small university that most hiring managers in the US would not have heard of.
To me the biggest downsides of university in Canada is that there is a risk of your student not returning to the US after four years, and the need to deal with the US tax system for Americans who have income and/or bank accounts outside of the US.
One advantage is cost. We had expected four years in Canada to cost about the same as one year in the US, but it actually ended up costing less than that. Another upside is the chance to see a bit more of the world in a relatively safe and “not so very different” environment. Another upside is that university admissions is so straightforward compared to admissions in the US.
If your student does return to the US after graduating university in Canada, this is a bit of a disruption to their life since all (or most of?) their friends and contacts will be in Canada.