I'm not in favour of it in the Canadian context. The only other example I'm familiar with is Australia. I'm sure that if we had mandatory voting, Canadians would, like Australians, get used to voting as not just a duty but the law. Of course, you can construct it so that fines for non-compliance are relatively minor, or you can escape it with a reasonable reason for not being able to vote. You can set it up so that it's not too onerous on people.
Honestly, I haven't given mandatory voting a lot of thought, because I've never considered it to be something that would be acceptable in Canadian polity. You'd have to prepare the way for it, I think.