Accessing children of instances vs children of original prefab

Questions & Answers
1

It looks like there is a major difference in accessing a child object using:

mainObject.transform.Find("Child");

vs

mainObject.Find("Child");

It looks like the first will access the children of the instance, and the second will access the children of the prefab (but not the instances)? Is that the main difference?

2

Are you using UnityScript and is mainObject a GameObject?

If that is the case, the first is calling the method Find from transform, while the second is calling the static method Find from GameObject class. The differences are:

1 - the 1st is a method from a Transform instance and the 2nd is static method from GameObject

2 - the 1st returns a Transform and the 2nd returns a GameObject

3 - the 1st searches in the children of the given transform, while the 2nd searches in all the scene