Not sure if this is still an issue in less ancient versions, but in 8.1.5 the export dialogue treeview is basically lag-free while importing the same export is extremely sluggish. Warning: Don’t try to use the mouse scroll otherwise you’ll be waiting a long time to do anything else while it catches up.
If it’s relevant, my project export is 23MB so a reasonably-sized project (515 views, 426 windows, 690 templates).
