The variety of lens perspectives are great. Ease of use, with the exception of horizon and loupe. Still haven't figured out how to use them yet. Simple interface. It doesn't take a rocket scientist to navigate or use the various tools. Fun to use! Sometimes I'll achieve some wonderfully quirky perspectives that I can use in my more creative works (other than just stock photography).

that everything flowed from one module to the next.... and you could jump around seamlessly

DxO is able to reveal and control details and colors in photos unlike any other imaging software I've tried. It is an integral part of my workflow - vital in controlling shadows and highlights in my RAW images (and also works with JPG). The ability to recreate a type of HDR without even shooting in true HDR style (merging) has been greatly improved and appreciated when a shot needs to have more details revealed n the shadow areas - or for reclaiming potentially lost highlights.