I forgot to mention one very, very big advantage of X1. IT COMPLETELY ELIMINATES THE NEED TO DO SEARCHES OF ANY KIND FROM WITHIN OUTLOOK.
All searches can be performed from X1.
If the X1 index is restricted to Outlook pst and or ost files only, it is extremely powerful. It eliminates the need to categorize or save email into different bins in Outlook.
The only Outlook folders I have for mail are "Inbox" and "Delete Items" (which is set to not be automatically emptied). Any message that can be deleted, unquestionably, is permanently deleted with Shift/Delete. Everything else goes in the "Deleted" folder and is permanently
saved until such time in the future when I decide to permanently delete them.
One could have additional folders for categories but in its simplest form this system works perfectly well.
There are many other good tools for searching all other types of non-email files but it is worth keep them separate from the X1 index if it involves large quantities/sizes of files.