Well, these 3 menu items should be really better explained in help. I also don't know exactly the difference. I can only write here what I can see.
Export Settings creates a copy of
- my currently used INI - exe-name.ini is default (uedit32.ini);
- my personal keyboard configuration file - ini-name.uek since UE v12.20 (uedit32.uek), previous versions have had the extension kbd;
- my currently used menu profile file - ini-name.mnu (uedit32.mnu);
- my currently used popup menu profile file - ini-name.pmu (uedit32.pmu);
- my currently used toolbar profile file - ini-name.tbr (uedit32.tbr);
- my currently used self-made (customized) toolbar configuration file Personal.tfg specified in the current INI;
- the 6 standard menu, popup menu and toolbar configuration files Advanced.* and Basic.*.
Import Settings overwrites the current INI and the other files with the files/settings in the specified folder.
I don't know if there is a difference for users who have specified to save all their settings in registry instead of the INI. Maybe
Import/Export Settings is mainly written for those registry using users.
Backup/Restore User Customizations was introduced much later than Import/Export Settings with UE v12.10 on 2006-05-15.
It gives the user more control over what is backup/restored. It offers also to backup/restore all the standard and currently used menu and toolbar profile files, but additionally also all files in the program directory of UltraEdit.
I think, it is most helpful for IDM support and developers, beta testers and power users which sometimes have to switch between different versions of UltraEdit (hotfixes for example). Well, I currently don't use it, because I have to switch often also to older versions which don't have a backup/restore user customization feature. But using this feature before installing a new version is always a good idea.
Main difference of
Backup/Restore User Customizations in comparison with
Import/Export Settings is that all selected files are stored in a single file and so a folder can have dozens of UltraEdit or UEStudio backups which makes it much more easier to manage the backups.
Either
Backup/Restore User Customizations or
Import/Export Settings should be used in a fixed interval by all users which use UltraEdit or UEStudio daily just for security of a data/settings loss as sometimes happens by accident or faulty hardware.