Another factor not to be ignored is currency. For Canroys who declare the distribution in Canadian Dollars, the fall of the U.S. Dollar has been an added bonus. If the U.S. Dollar rises, the reverse will occur. In any event, you're playing the currency market, something which is inapplicable with SJT.
Yes, this is also a currency play. My feeling is that the dollar will strengthen over time, weakening the canadian currency and making the canroys worth less then respectable other royalty trusts. Right now, sjt divy is 10.5%, I don't see any canroys that can match that, after you adjust for 15% tax loss/currency conversion.
The Canadian tax is deductible so has no effect on your US taxation--unless you've got it in an IRA, which I and many others haven't. The dollar up? Don't bank on it. The best I see is sideways in the long run.