Is Unity 5 different from Unity 4.6?

I am new to Unity Engine. I started with Unity 4.6 and followed tutorials from Digital Tutors for two weeks. Then Heard about Unity 5. Like every Computer enthusiast, I wanted to try the latest software and work on it. I downloaded it, installed, and double clicked the executable. The initial UI impressed me a lot. It was like I always wanted this type of UI in this Software. Here is the snapshot.

Not just that. Unity 5 have many internal scripting changes as well. User who used Unity 4.6 might have a tough time using Unity 5 in the beginning because there are near to none tutorials available for Unity 5 to take guide from. I used Unity 4.6 to follow Indie Game Development Pipeline when I was about to start Volume 3 of the series, I learnt  about Unity 5 and wanted to do all the work in Unity 5. Although now I have reached Volume 3 again, but there are many major changes in the code I used in 4.6. For example, 

here is use of "RigidBody" in Unity 4.6:

void FixedUpdate(){

            rigidbody.velocity = new Vector2(moveDirection, rigidbody.velocity.y);

}

and here is the use of "RigidBody" in Unity 5:

private Rigidbody rb;
void Awake(){
         rb = GetComponent<Rigidbody> ();
}
void FixedUpdate(){
     rb.velocity = new Vector2 (moveDirection, rb.velocity.y);
}

Here is another example of "Collider" used in Trigger

Unity 4.6:

void OnTriggerExit(Collider other){
       collider.isTrigger = false;
}

Unity 5:

void OnTriggerExit(Collider other)
{
GetComponent<Collider>().isTrigger = false;
}

This is just a trailer of changes I discovered by following just one tutorial series till volume 3. I am still discovering the changes and lets hope that I know and learn Unity 5 to its core so that I can create tutorials for you guys. After Pipeline I am going to follow Walker Boys Series with Unity 5 to discover more.