[Andrew Blair]

For FIRST, Inventor is king for a variety of legitimate reasons. It's easier for new kids to pick up and learn, it's more graphic, and especially when designing new parts and ideas, it's far, far easier to spit out a new design quickly and see how it meshes with everything else, without a sketch. As Tytus said also, it's very easy to change parameters once you've set up- something far harder to do with AutoCAD. Inventor is excellent for inventing.

That said, I do feel that AutoCAD is the top dog in industry right now, because it's been around, it's integrated, and it feels better to the people currently using the program. With an experienced person using it, I do feel that you can even be quicker than Inventor on some things.

Parametric programs have become very powerful, and I do believe that much of industry will merge in time. Inventor, SolidWorks, SolidEdge, and Pro-E are quickly gaining ground, and are used extensively in mold making and tool & die work, but they have not come into some larger, more monolithic business's yet. They may not ever, because some businesses simply do not need parametric, graphic programs. For FIRST though, Inventor provides an intuitive, powerful base with which to quickly propel your ideas. AutoCAD can't do that.