Reading these forums, and judging from my own experiences since upgrading to v3.3, it seems to me fair to suggest that Apple have once again prematurely released an inadequately tested turkey, leaving us poor users to do the testing and point out the bugs.
I upgraded a few days ago. I had nothing in iPhoto to merge, and the upgrade seemed to go well. However, using the new version, three things were apparent:
1) The "auto-correct" function does absolutely nothing. I persevered and tried it with over 100 shots freshly downloaded from my Nikon D3S and it altered nothing whatsoever on any of them. I can live without the function, ultimately, of course, but if it's a feature, it ought to work.
2) As I have posted elsewhere in a separate discussion (no replies yet, though), v3.3 seems to have problems with Nik plug-ins. Now, every photo I open in a Nik plug-in that handles colour has pink skies. This did not happen before the upgrade. The photos look fine in Aperture and are fine when exported, but when loaded to any Nik plugin, I get pink skies. All my plugins are up to date, too.
3) I too have had the experience of Aperture uploading photos to Photostream even though, initially, I tried to pause this and eventually switched it off altogether. Aperture just seems to be pressing on with the upgrades regardless. Others have been posting in these discussions about this, so the problem is not just mine.
Then, today, Aperture just hung on opening. I wasn't in a hurry, so left it for 30 minutes. Nothing. Force Quit said it "was not responding". I could not exit the usual way, and was left needing to force quit the app. When I restarted it, I got the message saying that Aperture had "detected inconsistencies in my Library". Well, be that as it may, the only way they got there was by something Aperture had, or had not done, because I had not touched the application, or anything using the photo library, since yesterday.
I began the instructed repair process for the library, and an hour or so later, it was clear it had hung at "99%". again, Force Quit was the only apparent option. Next time, Aperture opened - eventually. A full ten minute wait, and a further 30 second pause before any Project will open. Oh, and uploading to PhotoStream seems still to be going on, against my wishes.
And that's only to date. What on earth is going on?