My experience of Arch is that it's fun as a home computer tinkering exercise but I don't trust it for my work computer since I can't resist a version number bump and the amount of time spent faffing around would be a nightmare.
I think it can definitely differ between individual systems - the fact that Arch is so flexible also means that each system can have individual little foibles. Personally speaking, I've used Arch for work for the 3 years mentioned previously with no problems. At my previous job I used to be oncall for a week at a time and I wouldn't upgrade during those periods just in case, but that was the extent of my caution.
