I've switched from PMK to ABC pyro for all my film development and use both variable contast and graded papers to make enlargements and contact prints developed in Dektol and amidol, respectively. I switched because I get better prints with ABC. I started using PMK ten years ago because I got better prints with it than I had with HC-110. Why use a staining developer when the paper can't see the stain? Because the prints are better. Why are the prints better? I couldn't care less.