I used to do final/print sharpening in PS but since I started using QI I only do it there.  It is smarter and better.  My "middle" sharpen is a light Hi-pass.

Leaving things alone in PS (after initial sharpening--a must do) would work if you want to play with the QI editor sharpen and the equalizer.  The slider seems more for discrepancy between the RGB sensors in the camera.

I see where Mike goes with this.  Since the sensors, unlike film, are all on the same plane automatically there is a focus discrepancy between pixels.

Don't be afraid to use Normal in the print sharpening, instead of Smart sometimes.  It does fine detail sharpen only (per the manual), so has its place.  I have never found a set-and-forget sharpening number in QI.  I have a "normally" setting but I think subject, size, etc. benefit from playing around.

 

Yes, long ago.  I have real difficulty with using the term 3D on a two-dimensional plane without the aid of some viewing device that tricks you; i.e., 3D glasses for embedded effects, stereo viewing of 70% overlap, etc.
The other use is 3D rendering in drawings using shading, etc.

Mike and Uwe's use of the term presence makes the most sense!

But, isn't that what the slider does?  Affect the amount of sharpening based on the colors (well, original pixels) themselves.

Sure sharpness (along with other things) increases effective depth perception  in a photo.  Ansel Adams, et al, did it with B&W.

Some of the use of the equalizer slider that I have seen has taken those photos into the same realm as "super real" paintings.  Of course, the same has happened from some users of Photomatix.

Back to the item at hand.  The question I perceived is what works the best.  I don't have a best.  I think I said, 'try it all.'  It depends on the subject, effect, etc.

I don't think you are stuck on one catch-all product.  Some who won't/haven't/can't use other products in their work flow have to believe there is one way.  I have never taught that.  I used to work for a guy that had never ever used anything but Canon (pro stuff) and always says 'Nikon is junk.'  I have used Canon, prefer Nikon and think they are both great.  (Well, Nikon kicks butt with their strobe though.)   Since we brought Uwe into this, even he uses PS and Photomatix. 

Oh well, I digressed again. 

Isn't what I said true of what Mike and Uwe have written about the equalizer?  It corrects for (in simplistic terms) the differences between R, G and B receptors in digital.  Notwithstanding the abundance of green receptors, the failure of a lens to focus red, green and blue in the same plane is another issue that affects sharpness.  The thickness of the film and the location of each color layer was a partial compensation that we don't have now.  I am sure that will come.

Bottom line IMHO is use what works.  There is no lock for all photographs.