Which board is best -Edexcel or Cambridge board? and Which one is preferred worldwide?

I am just promoted to 9th grade and now I am confused between two boards, Edexcel and Cambridge. I can't really decide from which board should I be giving my O'level examinations. Someone please help me by telling me the difference between these two boards. By the way I want to go to USA to study to be a software engineer, so which one will be best for me? Please Helppppp..............