Why are users choosing Inventor over Solidworks? 

Exactly. It's frustrating to draw shapes in Inventor. On top of that, simple features like a shamfer that follows a curved 3D edge often fail in Inventor, Also updating geometry that's drawn top down in an assembly doesn't update correctly or ituitively in Inventor. I'm biased because I'm used to Solidworks, but it's been frustrating using Solidworks.