Testing and unstable cannot be evaluated for stability in comparison to the stable release. They work under a different paradigm.
There is a widely spread misconception about what "stable" means when referred to the debian release: stable
does not mean solid and reliable
per se, it means unchanging, invariable, in the sense that its components are almost "set in stone", only receiving minor and very attentively selected updates/upgrades, mostly just security ones. As a
consequence of that and the fact that before being released is
thoroughly tested, debian stable is
also stable as in solid, reliable.
To ask if testing or unstable are "stable enough" is to completely miss the point of what stable means for debian.
Testing and unstable, although in slightly different ways,
are not at all stable for the simple reason that they
change regularly, daily actually.
They are both stable as in "solid" if you ask me or all those who like me successfully run either one or a mixed version of all, but in the end
most will not find them reliable enough because
by design they are
supposed to break in order to find fixes for the next stable.
Anyone running testing/unstable should either have another system on the side for real production, or
has to be able to afford not to be productive when a problem arises, and it will arise, maybe not often in the form of a cataclysm but often enough in the form of something that
needs attention and time and research now!
If you think that turning your computer on tomorrow and finding that -from the top of my mind- vlc has stopped functioning, and you can live with it and devote time to research what caused the problem, then maybe yes, you are fine running testing/unstable.
If finding yourself with docky suddenly being removed overnight for a bug or a simple policy violation, a removal that may last a day or two or maybe ten or even weeks or months, then yes, you are gonna be fine with testing or unstable.
If you are fine with daily updates/upgrades, with reading all bug reports that come with them in order to avoid the biggest traps, with devoting occasional workdays to -say- restoring your ability to connect to a wi-fi network, then yeah, testing/unstable is gonna be A-OK.
If, on the other hand, you want a system that you can be sure tomorrow will work
exactly as it worked today, then
go stable,
backport and/or
compile from source and for the love of all that is good
never mix stable with testing or unstable.
Bye.
