Richard Green likes them. Nick Rowe does not. I can understand Green's antipathy toward the most common forms of adjustable-rate mortgages in the United States. However, I think that a mortgage that amortizes over 30 years, with an interest-rate adjustment every five years, and no teaser rate would be better than any of the common mortgages here. The five-year fixed term would suit many people, since many people move in less than ten years.
In any case, regardless of what Green or Rowe or I believe is the right mortgage, I think that the market ought to decide. It is my hypothesis that, in the absence of government support (including loading the tail risk onto taxpayers), the thirty-year fixed-rate mortgage with no penalty for either prepayment or default would be priced too expensively to attract borrowers.