Minimalist GNU for Windows
SourceForge provides a mechanism to distribute packages and releases. The MinGW team are using that to provide package repositories of Current, Candidate, Snapshot, Previous and Proposed. Each repository contains its own set of packages.
The Snapshot package is to distribute developer preliminary packages of approved Current packages that need testing and may have unknown bugs. You are encouraged to use Snapshot packages in your testing labs. However, if you find a Snapshot that out performs the Current version, then you may want to consider moving it to production and letting the MinGW team know that you feel the Snapshot is production ready.