I’m using Arch simply because of familiarity and comfort in using it. That and pacman being fast usually helps me make up my mind whenever I try something else. I really hadn’t experienced any major breakage in any of the packages in the standard repos, especially if everything is configured correctly. So I don’t really have anything to say against Arch’s stability.
I also hear good things about Tumbleweed, so that could be an alternative and more complete out-of-box package, but that also highly depends on how comfortable you’ll be with openSUSE’s way of doing things.
It all boils down to how you prefer to configure and manage your system and its packages, really. Nothing much more than that. As long it does the job, it’s usually fine.
The fountain of life