"The U.S. Congress established three key objectives for monetary policy in the Federal Reserve Act: Maximum employment, stable prices, and moderate long-term interest rates."Using this calculator the US has experienced cumulative inflation of 2254.2% since 1913. In other words, the US dollar has lost about 96% of its purchasing power under a century of Federal Reserve oversight.
While many lament the decline in the real value of the dollar and the impact of inflation on savers and fixed income holders, for my part, I believe that the Federal Reserve has done a mostly good job of steering the US economy through two world wars, the great depression, the inflationary oil shocks of the 1970s and economic cycles generally.
Any judgement of the Fed's track record has to take into account (i) that they are operating in an country where the political leaders habitually spend more than the annual tax take, (ii) that the US has remained the largest and (by some measures) most dynamic economy in the world over this time period and (iii) that the US dollar is still the world's dominant reserve and trade currency. Sure, the US's proportionate share of the world economy is shrinking, but this is largely because much of the developing world is belatedly playing economic catch up. For all its many and severe problems, the US has been a better place to live than most of the rest of the world during this time period. Lastly, it also has to be noted that the (on average) mild inflation over the last century has to have been a better outcome than periods of deflation which occurred regularly prior to the Fed's creation.
Of course, the Fed's track record has been far from perfect - contractionary monetary policies at the beginning of the Great Depression unquestionably made that even far worse than expansionary policies would have and we are still being haunted by the very avoidable bubbles of the Greenspan era.