We ran the numbers multiple, multiple ways. On the surface that sounds good and logical (get 5% and pay 2.84%), common idea and advice, we so looked at it, ran the numbers... then the bank started to recommended it until they ran the numbers with taxes... short answer, after tax there is an upside but it is not so compelling. The other game changer the decreased expenses per month (by paying it off) opens up other things like increased pension and ESAP that pay off more than double any potential after tax gains investing the sum. Not enough room in anything tax sheltered to avoid the taxes. We ran GIC (worst tax wise), we ran dividend paying stocks (can be better tax wise, but more risk), eligible, non-eligible, DRIP, different rates, etc.
Taxes are the rub.