Raghuram Rajan nails it in this Project Syndicate piece:
…More than any other policy action, monetary policy suffers from the sense that there is a free lunch to be had. Yet the interest rate is a price for the savings that are transferred to spenders. To the extent that the Fed manages to push this price down (and some economists will dispute its ability to push any meaningful interest rate down), it taxes the producers of savings and subsidizes the spenders of savings. Clearly, no government considers pushing down the price of any real good an effective way to stimulate the economy – any gain to consumers is a loss to producers, and the loss typically will outweigh the gain if the market price is a fair one. So why are savings different?
…This is not a heretical concern. As with any tax and subsidy, the net effect depends on whether those taxed cut back spending less than those subsidized. Economists have sensibly advocated that China raise the interest rates that it pays on bank deposits so that Chinese households earn more and consume more. Some Japanese now wonder whether their ultra-low interest-rate policy could be contractionary.
…There are many things that the US needs to do to create sustainable growth, including improving the quality of its work force and infrastructure. Easier money is not one of them.