Inventor vs Solidworks...

Hey guys I noticed that a lot of you tend to use Inventor as your CAD program of choice.
Do you guys use it because you can get it for free? Is it better then SolidWorks?
I use SolidWorks and I find it annoying when someone sends me a CAD file to look at and I can’t open it because they used Inventor and I use SolidWorks.

Is one better then the other? What are your guys’ reasons for choosing one over the other?