Hi John, your experience mirrored mine concerning the use of Photoshops Dust and Scratch
function ... until I had an expert retoucher I use for commercial work teach me how to use it more effectively. The secret is in 1) selecting areas, not application to the whole image, 2) doing it with the image at least 100% view so you can really control the pixel range 3) use of History brush for application and then the Fade tool for even more control. 4) optional use of channel application since in color work the degree varies by channel, just like it does with noise. Sounds complex, but isn't in practice.
So, I do not use it wholesale, but in a much more subtile and controlled way, and only as part of a ongoing dust control "system" of various steps as I mentioned above.
Also, I will be doing a ton of scanning after the New Year and am anxious to try my new "Arctic Butterfly" from VisableDust for the film prep. This is primarily designed for digital sensor cleaning, but I will be using it for film also. It is a motorized brush so you can turn it on and create a fresh electrostatic charge, turn it off and then it collects dust like a magnet. I was skeptical until Irakly cleaned the sensors on my Leica M8s with his. I immediately thought of a film scanning application as well, and ordered one immediately.