I've spent much of the last week dealing with bug reports for "4.3 rc1" packages that users have downloaded from various distributions. Sadly, these packages are usually not packages of the actual 4.3 rc1 that was announced just yesterday and so I'm spending time weeding out things that are already fixed in the actual rc1 and people are spending time reporting bugs that are get closed immediately as duplicates.
The distros tried to get packages out to testers to make sure the packages worked for launch day; fair enough. KDE also spent nearly eight days between the first tagging of rc1 and the eventually final release of it; that's too long. As far as I know, no users were informed of the situation and so took to testing the rc1 packages in good faith. They have done a great job uncovering bugs we've already fixed in the process. ;)
I'd love to see our betas and rc's have much shorter tag-to-release cycles, even if developers come up with last minute fixes: just release another rc a day or two later. I'd rather have seen us put out rc1, rc2 and even rc3 if needed over those eight days.
I'd also love to see distros inform their users much more clearly what those pre-release packages are so that they test what they should be testing: that the packages install cleanly.
In the meantime, for all of our valued testers out there: if you download a beta or rc release and it hasn't yet been announced on dot.kde.org ... it's not the actual release. It's a pre-release. Hold off on reporting bugs until the announcement is up on dot.kde.org and you've updated your packages one more time to make sure you've got all the updates.