One is single serve, the other is large jar.
Depends on what you need.
If you are just doing single beverage mainly then nutribullet is fine.
If you do a lot of food prep with blenders then vitamix or blendtec.
For margaritas or frozen drinks using ice, the margaritaville.
The small magic bullet is good if you travel a lot. Not as powerful but small enough to fit in suitcase.