To be clear: exceptions with both fixed and rolling releases do exist, but for the most part I've found that a fixed release distribution is more stable simply because it limits the opportunity for the user to break it.
I believe strongly that, for a business environment, a rolling release is just begging for extra work. Fixed release distributions in these environments allow IT staff to button things down and manage any needed updates in easy to digest segments. As a bonus, the IT team isn't left troubleshooting kernel bugs until they've set aside the time to drill deep into the upcoming release of their preferred fixed release distro.
Remember from above, less moving parts means less potential for breakage. If you control the update cycle with regard to kernel and desktop environment upgrades, you've won half the support calls right off the bat when dealing with common workstation errors.
At this point, one might surmise that I really dislike using rolling release distributions. Or worse, I have little to no experience with them. The answer to this, of course, was addressed at the beginning of this article. I've been using rolling release distros for roughly a year now. I can see the appeal of using them, but I also feel that there needs to be a clearer set of guidelines for when they make sense as an option.
For desktop users, I believe newbies should avoid using rolling release distros until they're more comfortable rolling back packages and/or overcoming sudden breakage. Whether it's something as silly as a broken GNOME extension that worked yesterday, or your Ethernet card suddenly stopped working, if you can't overcome these issues – avoid rolling releases.