What’s the difference between keymaps – Mac OS X and Mac OS X 10.5+?

There is the good explanation in help about the difference between two schemas:

1. the “Mac OS X 10.5+” schema is close to Mac OS default shortcuts. For example cmd+G is common Mac shortcut to find next matching text, cmd+O – open class – which is close to open action
2. the “IntelliJ IDEA Classic – Mac OS X 10.5” schema is close to IDEA shortcuts on other operation systems – Windows and Linux. For example cmd+N – open class – is close to ctrl+N to same option in Linux or Windows