I've decided that because I just did all kinds of maintenence and updated all of my backups- and because I'm going to be away from my workstation for a couple of days- I'm going to go ahead and upgrade my 100k image 700GB library.
I haven't been active on the forum for a while so any advice about potential challenges I might encounter would be appreciated. I don't use Faces or Places or any of that iPhoto stuff.
the upgrade to 3.3 and later was for some posters here problematic, if they neglected to make sure that the library had no glitches. In that cases the upgrade of the library failed. So I'd strongly recommend to run all Aperture Library First Aid Tools, before you open the library in Aperture 3.4.3 to upgrade it to 3.4.3.
Also keep a backup of your aperture 3.2.x library and a copy of Aperture 3.2.x to be able to revert.
Just in case you run into this problem: Aperture 3.4: May quit unexpectedly on launch after updating
The above problem can occur, when you upgrade from certain Aperture versions, that have the wrong plugin-manager framework installed. Then you have to revert to an earlier Aperture version and upgrade from there.
The latest Aperture version requires MacOS X 10.7.5 or later. Is your profile signature current?
Good luck for the upgrade!