In addition to the hosting plugins for Lightwave and other applications, Pro Pack offers the following:

Multi-pane document windows
Animated materials
2D motion blur
Python scripting for all those wonderful add-ons and other enhancements
No more corrupted geometry RSRs -- Pro Pack doesn't use them
No more need for BUM maps -- Pro Pack can use JPEGs directly
PNG thumbnails -- can be created and modified in most paint programs
Additional file format support
A setup room for rigging your own figures
Minor enhancements to the grouping tool -- AutoGroup and Weld