I have some new data on my site about Pyrocat-HD. See Testing Pyrocat-HD by Clay Harmon. I find Pyrocat-HD to be virtually equivalent to PMK, except that its stain is a different color. The stain color affects how it prints on VC papers, but that normally is not an issue for me.(posted 8053 days ago)I do not believe pyro developers are a fad. I have reproduced an article by Bob Herbst (originally published in View Camera), entitled The Effects of Pyro Stain in Platinum Printing, that clearly proves that staining developers (in this case the W2D2 pyro formula) can reproduce a longer tonal range than conventional developers (in this case D-76) for both platinum and silver. The extended tonal range is particularly important for me, since I photograph almost exclusively in Texas, Mexico, and the Southwest, where I encounter bright sun and deep shadows in the majority of my photographs. See particularly Herbst's Figure 4.