Offline Explorer editions include: Standard, Pro, Enterprise and Portable Offline Browser.
All editions have the same features set as Offline Explorer Standard has plus:

Offline Explorer Pro

• Full support of streaming media protocols - MMS, MMST, RTSP, PNM and NSV (ShoutCast)
• A separate download directory for Project folders
• Nested folders in Projects tree
• Downloading queue manager with the ability to selectively stop URL downloads, sort queue, etc.
• Data Mining - post processing of downloaded Web site
• Ability to prohibit the Internal HTTP server from being accessed from other computers
• Ability to print the whole Web site
• Ability to change the directory in which to keep Projects, templates and maps
• View detailed Project download statistics
• Enhanced Export features:
  • MS IE cache, MHT, searcheable HTML Help (CHM) files, compressed EXE viewer
  • Upload to FTP site
  • Option to export rto a plain directory with no subfolders
  • Customize Contents.htm files before exporting Web sites
• Project settings include more powerful features:
  • You can set it to load from starting server and up to X links on other servers
  • Ability to keep old copies of loaded files
  • Additional Project description window to supply multi-line comments
  • Content Filters to specify actions (save, discard, stop downlod, etc.) if a certain text was found or not found on downloaded Web pages
  • Filter images not only by size or location but also by its dimensions (in pixels)
• The Project's URLs field is multiline and it allows to specify an unlimited numver of URLs, additional commands, macros, etc.:
  • URL macros modify links to include current dates, specify download range (e.g. from 1 to 99 similar pages), make variables and so on.
  • Automatic Export of downloaded Projects
  • Custom referrers, cookies and post requests
  • Start programs once Project download was started or finished
  • ...and many other - simply press F12 inside the URLs field to show the list of all commands.

Portable Offline Browser is a special Offline Explorer Pro version.

It can be installed to a Flash/USB drive and run directly from it. You can plug the drive with the installed Portable Offline Browser into any Windows system and use it with no need to adjust settings. All your Projects and downloaded files will be there! And when you unplug, none of your personal data is left behind.

Offline Explorer Enterprise adds to the Offline Explorer Pro edition features:

• The ability to download up to 100 million URLs per Project
• An OLE Automation interface to enable control from other applications
• The ability to update Projects with deleted files
• Internal Proxy server to access downloaded sites transparently in your browser
• Generation of Google SiteMap files
• The fastest-possible multi-threaded processing of downloaded files by using all CPU cores