[_yy]

> I didn't have any update-induced downtimes yet, except for the usual reboots to apply kernel upgrades

Wait until the first major backwards-incompatible config format change breaks something. Puppet was one example of many.

> My solution is to package that software myself in a private repo, so that I get to decide when to upgrade.

Works fine for single applications, breaks horribly for system-wide shared libraries.