I can only really speak to artsci
Pros: diversity in courses, you are able to specialize in virtually any field, you get some of the best profs in the university (or the country), faculty events are frequent and lots of fun, and you can pretty much do anything once you graduate, including med school.
Cons: it may be difficult to get into some courses if you aren't specializing in that particular field, but it can be done. there may be more, but i can't think of any atm.
I hope that helps a bit. a lot of people will tell you that healtschi is easy and lame, which i don't believe, but i have been told that health sci is essentially prep for med school whereas artsci can be a prep for a number of things, including med school.