It's been nearly five months since Adobe launched the GPU-accelerated Flash 10.1 beta, and although the final release is still dormant, the release candidate is now available with various fixes and enhancements. The latest build is available for Windows, Mac, and Linux, and you can read the official release notes here (PDF).
There seem to be dozens of changes in the latest release, including many video playback bugs on Hulu, CBS.com, and ABC.com, as well as malfunctioning H.264 acceleration on Broadcom Crystal HD decoders. Adobe also mentions "general stability and performance improvements," and notes that users may require updated video drivers (AMD, Nvidia, Intel, Broadcom).
While numerous bugs are resolved, there doesn't appear to be any major new features, unlike some previous stages which, for instance, added support for Crystal HD chips. Nevertheless, if you've been waiting for a more polished release to give 10.1 a whirl, now seems like a good time.