Are there major similarities and differences between U.S. GAAP and IFRS

Are there major similarities and differences between U.S. GAAP and IFRS

Are there major similarities and differences between U.S. GAAP and IFRS? Which of the differences do you find most interesting? If there is a convergence between U.S. GAAP and IFRS, would you choose the U.S. GAAP or IFRS method? Why?