I asked in this question how I could introduce additional handicaps into StarCraft 2 to make it easier to play with my friends without relying solely on the built-in handicapping system. However, it just occurred to me that I don't actually know what the built-in handicapping system actually does.
What does the built-in handicapping system do, precisely? Does it affect unit HP, attack power, income rate, or other things? Does lowering the handicap percentage from 100% help or hinder you?