I have been using PWP since I started Digital Photography seriously. It unlike all the others is transparent in its processes and when used with the excellent White Papers that accompany the application inform the photographer about some of the "dark mysteries" surrounding digital processing. Someone said of it that it applied an analogue approach to a digital process...a bit like using a dark room. While I now use Capture One and DxO as well, PWP still forms part of my workflow particularly when the out put is a print. The Graphic User Interface is Windows 2.11 and the dcraw demosaicing lacks finesse particularly with highlight recovery but it does some things really well. The creator Jonathan Sachs (also of Lotus 1-2-3) is an unsung hero.