I will acknowledge that there are people who do stupid things. When they can afford a $400 payment they lease a BMW instead of Buying a Honda Accord. Same is true of housing. Got to keep up iwht the Jones. But when used effectively the math seems to pan out OK. I am not going to say it is for everyone but anyone who can handle a 30 year conforming mortgage should look at both products and ask themselves if they might not be better off investing that difference. For many people they would frown if you offered them 5% on and investment yet they would throw money at a loan and try to prepay it back. Just doewsn’t seem consistant. If on the other hand you feel snake bitten by the market and have elected to go with CD and Govt Bond then I would say the 30 year conforming makes sense and would even advocate that a lender provide a 15 year amotrtization schedule so that you can set your sights on making those monthly payments. Just my read on finance decisions.