Although every FME beta build undergoes thousands of automated nightly tests, they are not as thoroughly tested as a service pack or annual release. For mission-critical production streams, we recommend an official FME release.
If you want to include some production workspaces in our tests, please fill out our support form with "TestSuite Addition" as the subject and include any relevant workspaces and data. We'll discuss with you the best ways to include a subset of the data into our tests.
Stay up-to-date on the latest beta releases by following @FMEBetaBuilder on Twitter.