If you don't want to perform the physical comparisons simply pick one and believe it's the best. No two engines are the same, especially with different manufacturers. OS will be different from Magnum, which will be different from Thunder Tiger, which will be different from Tower, which will be different from Irvine. Now factor in engine conditions and fuels. You have asked a question that is impossible to answer.

To do some of the math yourself go back to last months issue of Model Aviation and read the propeller article by Andy Lennon.