WIP Portal:Factory/Intro
The Factory distribution is a rolling distribution that is the base development for the next openSUSE release (the release timeline can be found here). The development releases of the openSUSE distribution like Milestones or Release Candidates are snapshots from this distribution. There is constantly work going on in Factory. Every time a developer submits a fix, version update, new feature or new package it is built. So the Factory repository can be in any state and is a moving target. Only the development releases do get some basic testing before the release. Each of the architectures is synced to the download server only when it is in a consistent state e.g. all builds have completed. That usually happens only once or twice a week.
Hence it is mainly useful for developers and experienced testers. They use it as an always up-to-date development and testing platform. If you rather look for a more up-to-date openSUSE without the instability that comes with Factory, try Tumbleweed.