I have 192Gb of 999Gb left
That should suffice.
I have now disabled FACES, XML and previews. I'll test this shortly to see if it helps. I'm not sure what difference this will make to other apps.
That will be important, when you want access the APerture library from other applications using te Media Browser or when you want to sync your images to your deviced usin iTunes. For images, that you want to use in the Media Browser you will need previews, or for browsing your aperture library in quick Preview mode. You can craete previews indivudally, if you do need them only for selected images. If you want to use the Media Browser with third party applications, however, you will also need the XML. See:
Aperture 3.5: Set "Share XML with other applications" to "Never" for better performance and faster quit times
Okay. I've closed Aperture and reopened it 4 times. It appears to go through this 'IMPORTING FROM iCloud November 2013' every time.
Either it takes a very long time, or there is an image or a video in your Photo Stream that cannot be imported, because it is incompatible or corrupted.
For iPhoto libraries it used to help, to remove the current "Importing" or "Auto Import" folder from the library package. Try, if this will help for your Aperture library.
See this post by LarryHN how to do it:
TS3745 Re: iphoto library error message???
If you cannot get the import to stop this way, post back, Then you have to delete the photos from your Photo Stream or reset the Photo Stream.