The latest nightly build of the Reason CMS can be downloaded at the following url:
The builds are packaged just like any official release, and should generally be quite stable. Reason development proceeds at a fast pace, and the build typically changes daily. The current nightly build is essentially Reason 4 Beta 5 prior to some documentation changes.
If you have problems installing or using Reason, please don't hesitate to contact us through our support list - email@example.com