Here is a simple example (the math isn't simple, BTW).
Imagine your investment entities were all of an identical growth rate. Furthermore, imagine your future comprised a traditional... 'working til retirement', 'saving for retirement', 'living off savings at a constant inflation adjusted (after tax) lifestyle', and finally, that our taxation and entitlement (CPP, OAS, GIS, clawbacks..) environment remained constant.
The latter item assumes that tax brackets, CPP/OAS, clawback thresholds, etc are indexed to inflation.
When you run a plan under those assumptions, it will almost always turn out that the RRSP strategy outperforms the TFSA strategy (albeit slightly). Now, since the TFSA has no taxation component, then it stands to reason that the RRSP will outperform a nonregistered investment with any mix of dividend, capital gains or interest.
The caveat is your estate plan. In some cases, choosing a non-rrsp investment will turn a better outcome (to your estate) if you die much earlier than you had planned. If think you might not make it out to a ripe old age, you might want to look to the TFSA or taxable investment.
Finally, the TFSA is useful if you anticipate needing a largish lump sum withdrawal for a major purchase.