I've been on team
@Spekkio for most of the debate in this thread. Bottom line is the government rolled out this plan to SAVE MONEY, and on the whole, it will do just that. Sorry
@DanMa1156
BUT, I have to vehemently disagree with paying off the mortgage early at only 3.5%. I just can't get enough 30 year debt locked in at 3.5%! I have 4 mortgages in the range from 3.5 - 4.5% and the interest is either a tax write off (up to only $750k now, but still good) or a tax write off (investment properties). Five years from now you could very easily be buying a car with a "good" 5% loan. Heck, people with bad credit have to pay 5% or more for a $20k car loan. By happy accident of timing I am fortunate enough to continue with a $300k loan at only 3.5%. Reduced cost of living at 46-60? Give me that time value of money for the next 15 years, and I am confident I can beat your 3.5% hurdle rate. Furthermore, if I am only beating a 3.5% hurdle I don't need to hit home runs. I can be conservative, which decreases the expected volatility of my returns. The money I'm not wasting by paying down my mortgages early I am investing in the stock market and earning tax free compounding (Roth IRA and TSP). Boom, now you are diversified to boot.
The only time I would recommend anything like what you are talking about is if you live in Australia. They have this crazy thing called an offset account. Basically, if they put extra money into a special escrow account called an "offset" it lowers their interest rate. Also, most other countries in the world don't have the option of fixed rate mortgages like we do.
If we ever go into a true deflationary environment (beyond what Japan has seen recently) for a long time, paying the mortgage early will have proven to be a smart bet. But if that happens, things will be so crazy weird that I think all bets are off.