Not in SF, but talked to a number of Canadian founders when I worked in VC.
It depends on your financial/legal situation, those of your co-founders(if any), and what types of "returns" you are referring to by ROI.
1) The obvious benefit is to get plugged into the network there. You don't need to be there all the time to accomplish this. Waterloo, and Canada in general, is still cheaper COL wise compared to Bay area/NYC etc, so it'll help with your burn rate to build in Waterloo. Most people's burn rate at least doubled when they move themselves or their team. Flying in every few months could be enough.
2) If you're convinced you need to move to the Bay area, it might be useful to incorporate your business in the US and look at your visa options. I think there's a regular Ask HN about immigration issues. You likely need to do this anyways if you're fundraising in the US. The typical setup is some sort of Delaware corp with a Canadian subsidiary, if needed. IANAL and you should get professional advice here.
3) Get married to a US citizen and your personal visa issues will be solved lol.