Adding my me too. I installed 4.3 yesterday and used it to export one of my blogs. It was pretty slow, but it was flawless.
I installed the same version of the plugin on another blog and the export is stuck at “Done creating an empty archive”.
I see where the plug-in created a file under /wp-content/plugins/all-in-one-wp-migration/storage/0w2gyuwb2ljz# with today’s date and a .wpress extension, so I don’t believe permissions are an issue here.
Both blogs are running wordpress 4.3.1 so it can’t be that. And both of these blogs are hosted on my own server (no AWS, hosting company, etc.).
This is very frustrating considering that I forked over the cash for the unlimited option.