Some screenshots for your pleasure.

(Click on the thumbnails, to get full size images.)
The main window. Files are shown by directories, not all in the same lister, as in WinZip. Browsing is as easy as a double click on the directory name.
The GUI is highly customizable: buttons, toolbar, layout, columns, columns order and sorting...
Preferences window. Several options available, for both beginner and expert users.
The adding window. The tree showed in the right side will be packed into the opened archive. The image of the tree is kept in memory, no need for temporany files or directories to build complex archives. It's just a matter of drag & drop in the right place.
If you're too lazy to click on three directories, you can reach your nested directory by opening the PopBrowser, that let you select a directory from a confortable tree view of the archive.