Look I will keep this simple I'm not here to be impressed by any distro.
Archlinux is great, Slackware is great, Gentoo is great, Debian is great, fedora is great, Opensuse is great...
It will come down to your understanding of a stable operating system. If u update any of the above Distros with unstable packages then ur chances of making an unusable distro gets really high.
Growing Pains in Linux
Since Ubuntu is taking the first steps towards a touchscreen Gui. It has been meet by hostility. Is causing lots of ripples across the Linux Community.
hostility is a form of angry internal rejection or denial in psychology.
What Ubuntu has under estimated is the number of desktop users without a touchscreen monitor. So this Unity desktop has funcutional problems.
Were now most users are Saying Linux Mint is the best Debian/Ubuntu based distro.
As far as the most stable Linux Distro it is up to you to put a system in place to avoid problems across all linux distro's.
Linux community needs to come up with how to maintian a stable linux system across all Architecture on any linux distro and any hardware.
Architecture is both the process and product of planning, designing and construction.
Since most of the major Disto's are like brothers to each other. One brother is trying to outdue the others. Well this has been going on for as long as OS has been around Unix, Novell, Apple, Windows , Linux and soon to be Android.
With this being said only Slackware and Unix seems to be the only Os's that has came at it from approach of Stablity. Every other OS has tried to reinvent the wheel everytime. For a while it works then they get over ambitious and start out on a new idea.
am·bi·tious 1) Having or showing a strong desire and determination to succeed. 2) (of a plan or piece of work) Intended to satisfy high aspirations and therefore difficult to achieve.
Now as far as a Human. Humans are the greatest manuplators on plant earth. For every post on here that says this Linux Distro doesn't run good. I can tell you there would be 10,000 + users that could tell you how they made it sexy, fast, reilable and easy-to-use OS or Linux Distro.
Any human can show the weeknesses of a OS and what it can't do well and what it can do well. It is upto the reader to take 1 of 2 approaches. 1 ) I will work with what you have given me and find away for the system to work through mathmatical process to accomplish my goal. 2) I will find a product/OS that meets my needs exactly.
Well have fun Distro Jumping!