Padding is for inside/within components. Eg. TextView , Button, EditText etc.
Eg. space between the Text and Border
Margin is to be applied for the on-outside of the components.
Eg. space between left edge of the screen and border of your component
Visual representation is great in : Difference between a View's Padding and Margin
With Padding, i have seen a difference in 2.2, 2.3 and say 4.3, 4.4
in such cases:
Also, check the use of dimens:
http://developer.android.com/guide/topics/resources/more-resources.html
