Sure thing ailmanki but I’m using those Radiants just like all of you so I supposingly don’t know more than you do.
Anyways, I just checked the Radiant changelogs.
[table=“width: 500”]
Changes made in GtkRadiant 1.5
[HR][/HR]
Games:
•Doom3 and Quake4 support with realtime lighting preview.
•Return to Castle Wolfenstein.
•Wolfenstein: Enemy Territiory.
•Star Trek Voyager: Elite Forece.
•SoFII Double Helix.
•Quake I/II/III/IV.
•Jedi Knight II: Jedi Outcast.
•Jedi Knight Jedi Academy.
•Half-Life.
•Doom3.
File Formats:
•quake1/quake2 *.pak
•quake1/half life *.wad
•doom3/quake4/half life .map
•doom3 .md5/.def/.mtr
•quake4 .guide
Undo Function:
•Uses minimum memory, allowing very long undo queues.
All scene modifications now undoable, including:
•Texture name/shift/scale/rotate on brushes and patches.
•Vertex/edge/face manipulation.
•Cloning, deleting, pasting, importing.
•Entity key/value setting.
Selection:
Per-polygon selection for all selectables, including:
Vertices, edges, faces, brushes, patches, models, entities.
Per-polygon area-selection for all selectables.
Edge/Vertex/Face mode automatically resets to Object mode when selection is cleared.
GUI:
•Instant window updates (used to be 40fps limited).
•Fast startup/shutdown.
•Automatic repositioning of separators in 4-way-split mode.
•Console prints all undoable commands (and parameters) when executed and undone.
•Status bar shows mode information.
•New preferences layout, unused settings removed.
•Rearranged menus:
•File = new/open/import/export
•Edit = manipulate scene hierarchy and selection
•View = toggle entityinspector/entitylist/surfaceinspector/camera/xy
[INDENT]•edit camera/xy parameters[/INDENT]
[INDENT]•filters/hideshow/region[/INDENT]
•Modify = transform scene elements
•Build = bsp menu
•Upgraded win32 gtk2 version from 1.3 to 2.4, providing stability/cosmetic improvements.
Features in GtkRadiant 1.4
[HR][/HR]
Games:
•Return to Castle Wolfenstein.
•Quake III.
•Wolfenstein: Enemy Territory.
Selection:
•area selection in 2d view:
•Alt+LMB (LMB=left mouse button): area select
•Alt+Ctrl+Shift+LMB
•NOTE: with Alt+multidrag enabled in preferences, you only have additive [that’s what I called paint-select]
[/table]
These are just some changes out of the changelog from the Radiant. If you have a look at it you see that there were actually no changes from version pre-1.4 to 1.4 but a lot of improvements/fixes from 1.4 to 1.5.
Since NetRadiant is based on GtkRadiant 1.5 all these changes/features are aswell in there and supposingly a bit more since the NetRadiant-developers also enhanced their Radiant compared to 1.5 version of Gtk
If you want to know all changes just read the changelog.txt in the file-directory 
EDIT: Found something for NetRadiant on their homepage.
Regards
KeMoN
