Wheezy, version 7 of the operating system Debian, was declared the new stable, official, version on May 4th. I use Wheezy as my main system since some time last year. When Wheezy became stable, the testing recieved its new name: Jessie. Which will be the future version 8, when it in its turn become stable (at least 18 months from now). If you want to try Jessie/testing, snapshots can be found here.
Testing is usually stable enough for a desktop install, unless one is very concerned with stability. I remain on Wheezy for the time being. But as soon as Wheezy went into stable I installed testing/Jessie on an extra harddrive, just to see what happens in that release. For the config file for the package manager (/etc/apt/sources.list) I put in "jessie" but it did not work. It had to be "testing". Later I changed it to "jessie". It really does not matter as long as Jessie = testing.
I do not use my Jessie install much, all configs remain default. It is a somewhat barebones KDE install, as my main is. It does not even look like Debian. The KDE theme is stock version.
Quickly, Jessie jumped its kernel version from 3.2.x to 3.9.x. I did not notice any strange things. At the moment of writing it is 3.10. Wheezy/stable is still on 3.2.x. Jessie KDE has just been upgraded from 4.8 to 4.10. So even if testing is not bleeding edge, it is quite quickly updated.
With time, the gap between stable and testing widens with timewill widen. Stable (Wheezy) basically only recieves security updates and bugfixes. The repository wheezy-backports holds some commonly used packages in newer versions. That repository is for Wheezy users only.
Addendum: I wrote this post in late August, but due to some major computer cockup - partly my fault, partly hardware problem, I never got around to post it. Maybe it jinxed my computer. I am slowly recovering. The two installs I am writing about here does not exist anymore. Stay tuned for more posts on my testing adventures.