Nightlies
From MozillaZine Knowledge Base
Alpha, beta, nightlies and release candiates - what should I use?
- Alpha - early in development (not stable)
- Beta - early in development (not stable)
- Nightly versions - test versions (not stable)
- Release candidates - test versions (possibly not stable)
If you want a stable and reliable solution - use a release. All other versions are to be considered as to be used for testing - only.
They can be stable but they can also have bugs - serious functional ones at worst. However if you want to get involved and want to help with development - using a testversion is a great way to do it. During development it is always important to test any new function/version in various enviroments. Things has to be tested.
Reporting bugs and problems is always appreciated.