I think that stability can mean a lot of different things but in most cases all the major Linux distros are very stable.
It is all about personal preferences and tolerances for things not being “right”. I think much of the perceived instability/stability comes from how long a distro waits before updating to new major versions of applications. Arch does this very quickly which means that you get to play with the latest stuff but it also means you are one of the earliest users of those applications and there is a greater chance of finding problems. There are other rolling release distros which are more conservative about when a new application version makes it into the repos. The same is true of static release distros. Think about Fedora from a few years ago where they were tossing in the latest bleeding edge stuff into each new release without enough testing. They used to always be unreliable in the early months of a new version.
I am not sure that being rolling or not is a good indicator of stability.