I have used both, currently using Inventor, might be switching back to Swx. Here is what I have found over the years.
Inventor has far superior BOM management.
I like inventors frame generator better.
Both are user friendly and easy to learn.
Inventors derive feature is far superior.
Inventor has more control over adding balloons in drawings.
Except for Autocad, I don't use any of the other software bundled with the suite, I don't even install it.
But
Swx integrates with Rhino much better.
Swx handles topology changes much better.
Swx is fully associative, Inventor is not. Copied straight from the help Projected cut edges are not associative in a sketch. The geometry is a "snapshot" of the geometry when projected, and if the parent geometry changes, does not update (Yes I know there is a work around, but Swx does not need a work around)
Swx can send assembly features back to part level, inventor can not. (yes there is an add on that provides a work around, but again Swx doesn't need an add on)
Swx has more mate options.
Swx has multi body sheet metal parts, Inv does not.
But Swx future is unclear as they may be switching to the Catia kernel, might be powerful, might be a disaster.
If it wasn't for the BOM differences I would switch back to Swx in a heart beat, but BOM is a big deal for me so not sure yet.
Both have their limitations, so you have to see which limitations affect you the most, the problem is the resellers wont tell you about them. Insist they demo by modeling and editing something that is relevant to your industry.
If you work on your own, don't care about industry standards, don't need piping and don't need a frame generator, have a look at Ironcad as well. It has a very powerful mix of history and direct editing.