Blender's internal representation of objects is vertices (defined with IEEE single precision floats) connected by lines, and faces --just the shell of the object, and no real curved surfaces (just more and more faceted to approximate curves, and smoothed normals to look curved.) It also does not have guaranteed precise measurements. Blender can do some parametric and Boolean operations and many of the same things, but sometimes it fails and the limitations get in the way.
Some have built CAD tools into Blender, but it's a hack on an artist's tool. For some types of CAD projects, it'll do great, particularly in some very creative directions, but I'd start with the other tools you mentioned.
I export Inventor models to Blender for better rendering and animation.