Catia 3DX vs. 3DX Engineering

Hi, everyone.  
I hope I'm in the right forum here.  

I'm relatively new to the 3DX world and was planning to get one of the student packs soon.  Now I ask myself what is the difference between 3DX Catia and 3DX Engineering and which version you would recommend as a more experienced 3DX user.  

I am happy about every answer