Stability of Arch Linux
Arch Linux is very stable (much more than, for example, Ubuntu, at least from my experience), provided you know what you are doing and configure your system in a correct and responsible manner (see the Arch Way).
Of course, this will seem daunting to most people, but luckily the documentation is amazing and the community very reactive, so don't be scared. It's embarrassing that the article fails to mention it, so I will say it one more time: have a look at their wiki, it is a-ma-zing and will be useful even if you don't use Arch.
Arch is the perfect distribution if you want to (amongst other things):
* have complete control on your system.
* improve your knowledge and understanding of Linux.