As a contrary anecdote, Arch Linux has only gotten more stable for me over the past years. I'm running it in multiple servers and had only one incident where a downgrade was necessary (which is not particularly hard either).
Eh, I also do that and in fact, archlinux.org and all of its servers are also hosted on Arch Linux. It works really quite well and there is little reason to suspect it should be any less stable than other distros.
Last I checked the Arch website was run by a Debian box, not to mention funded by Debian.
I'm fairly knowledgeable about our (Arch Linux) infrastructure because I set up a big chunk of it. I'm not sure where our donations come from, though.