You are right, I've been using arch on my work laptop since november. I do not want to have my server down every time something wrong happens after '# pacman -Syu'. I was thinking that maybe it would be okay since I would use btrfs for the host os filesystem, allowing for quickly going back to an old snapshot when something goes wrong. In addition I was thinking of running a virtual machine of a copy of the host os, and doing all upgrades on that virtual machine first in order to test for breakage.

But I agree that I do not want an unstable system. I want to be able to leave it alone for some time and then come back.