You forgot to mention the currency risk with your 3% mortgage. If the Peg were to be removed and the HKD revalued up 10 or 20% that would set you back a bit. Or if the AUD suddenly collapses 10-20% that would sting...it fell 10% in about a week late last year - my bank was busy doing margin calls on its mortgage clients.
And it wasn't so long ago when the HIBOR was in excess of 10%. Enjoy the low interest rate now but don't try to sell it as a risk free venture. Those that have done Yen or CHF carry trades vs the Aussie could get badly stung if exchange rates go anywhere near back to historical levels. You dont think that can happen? The AUD has gone from 82 to 56c in 2 years and from 48c - 80c in 2 years. Better hope you get back in to the AUD, and those 9% interest rates, at the right time or you will be sitting on a large capital loss.
And whilst you are paying only 3% your
VB buddie is effectively paying 4% if he is in the top tax bracket thanks to negative gearing on his investment property, with no currency risk. So really there isn't that much difference between them and us except we have this huge currency risk that has lowered an average CX FOs salary to below that earned by
VB FOs. And for that he gets nearly half of every month off where the air is clean and there are labour laws.
When it comes to your gambling on exchange rates and interest differentials, I would ask 404 for advice - he used to play with this stuff for a living.