Sure, sure, the recent 100% CPU load on screenlocking bug on KDE 4.10.x for some people was really fun, I suppose.
No idea what you're talking about. I tried googling it but found nothing.
I have no idea what kind of "crucial for productivity" you need to update that often from the damn desktop /environment/.
I was referring to PIM applications. If you could read, you'd knew that.
As for the PIM if you value your crucial thing - just don't use KDE PIM period. It's just that bad.
Kontact 4.10 is great: http://www.muktware.com/5567/future-and-kde-pim – 4.8 however was only the second release with the new foundation. It contained bugs related to mail filtering. These bugs are all fixed in 4.9.x or 4.10.x, as far as I'm aware.
Evolution 3.6 also bought nice improvements.
As for non-PIM productivity applications: GNOME Boxes 3.4 is a mere tech preview. 3.8 is the current and much better release. GNOME Web is now based on WebKit2 which is a great improvement security-wise.
As I previously wrote: QtWebKit 2.3 has also been released with many important bug fixes but Debian 7.0 sticks blindly to QtWebKit 2.2. EVERY Qt-based application that uses WebKit to render some content has grave security risks with 2.2.