KLook gets PDF/ODT support, while StackFolder gets drag-n-drop
KLook is a multi-file-type viewer. It is not an application that can be started standalone, but is integrated into other applications, like Dolphin, KDE’s file manager. StackFolder, on the other hand, is a widget application that makes it possible to browse the contents of a directory, or your entire home folder, without opening Dolphin.
Read the complete article at http://www.linuxbsdos.com/2012/06/28/klook-gets-pdfodt-support-while-stackfolder-gets-drag-n-drop/