I don’t get the impression this guy is a troll so at the risk of looking naive I’ll state the obvious:
Any Non-Traditional mortgage, Adjustable, interest only, or (the now defunct) negative amortization is essentially designed to do one thing: get you into a house you could not otherwise afford.
It may save money in the short term, but then what? If you don’t have a bulletproof answer to that, than you should go traditional. And “I will take my equity, pay off the loan, and buy something else” is not a bullet proof answer in today’s market.