Seriously overrated Presidents include John Adams, sometimes Andrew Jackson (Some people love him, some hate him, the ones that love him seriously overrate him), Lincoln, Teddy, Wilson, FDR, and pretty much every president post World War II that isn't hated by everyone on the planet (Reagan was the best of those, but was still pretty bad compared to earlier, more free market presidents.)
Seriously underrated guys include Van Buren, John Tyler, James Buchanan, Grover Cleveland, and Silent Cal.