I am Canadian and have several properties in the US. Two things:
1) I used equity in my home in Canada to fund purchases rather than taking out US mortgages. Within the constraints of the available equity that strategy has been good. (a) the interest rate has been considerably lower than I would have paid for US mortgages. (b) I was able to act more quickly and decisively and probably achieve slightly lower purchase prices because the offers were then cash offers. One downside is that the Canadian interest cannot be deducted against US rental income according to the IRS because the debt is not registered against the property. However it can be deducted in Canada so I think that works out ok. Anyway my interest rate has been at least 2% lower so even if my specific tax situation was such that I didn't get all of the deduction benefit in Canada it still would have been financially better than using US mortgages.
2) this one was a mistake. I went with holding properties in US (Arizona and Ohio) LLPs. Reasoning was that tax rates in the US for both rental income and capital gains were lower for properties held personally from a tax perspective (in own name, or in LLP or LLC) than for those held in a corporation. So that ruled out a corporation. And LLCs faced double taxation while it was said that LLPs wouldn't. Hence LLPs.
Now, well after that decision was made it has turned out to be a mistake because the CRA in Canada is in the process of changing their position on Partnerships with limited liability (LLP, LLLP). So far they have ruled that partnerships in Delaware and Florida are now going to be treated as corporations in Canada which means double taxation. Foreign Tax Credits cannot be used to claim back personal income tax paid in the US against corporate income tax due in Canada, and the CRA is now saying they see that income as corporate income. It is likely that they will expand this to partnerships organized in other states. That means I will have to convert my LLPs to LPs which means losing the liability protection, but retaining the administrative complexity (additional tax submissupions for each LLP). This is a very disappointing act by the CRA which seems to only hurt Canadians without generating any benefit to anyone. The whole point of the tax treaty is to avoid double taxation and they are creating a technical argument to void that intent, but there it is.
If I had to do it again I would have simply held the properties in our own names and mitigated risk with extra liability insurance. It isn't the same as the liability containment of an LLP, but does reduce risk, and in my opinion the double taxation issue now rules out use of limited liability partnerships for Canadians investing in the US.
I would be happy to hear others' opinions and interpretations of the tax rules. If you want more information on the LLP tax issue I am referring to, simply search on LLP and CRA and Delaware and look for entries starting around May 2016. You will also see entries around December talking about how the CRA is going to be generous and give us until the end of 2017 to convert LLP/LLLPs to LPs to avoid the double taxation.