Today, Microsoft released Windows 10 for PCs build 16281 to the Fast ring of the Insider Program, but the Slow ring got some love as well, with the release of build 16278. Interestingly, that build was offered to the Fast ring just three days ago, which should speak to the stability of what's coming out of the Redstone 3 Development Branch.
You won't find a lot of new features; in fact, the only build that's been released since then with some solid new front-facing features was build 16257. That contained the new Eye Tracking accessibility feature, Edge improvements, the ability to change the colors of the Console, and more.
Other than that, Microsoft is gearing up toward finalizing the Windows 10 Fall Creators Update. The company announced this morning that the new feature update will begin rolling out to the general public on October 17, and since Slow ring builds are typically monthly (the last one was 16251 on August 2), the next one very well may be RTM.
If you're on the Slow ring, you can get today's build through Windows Update. If you're not and you've decided that now is the time to try out the Fall Creators Update, you can sign onto the Insider Program by going to Settings -> Update & security -> Windows Insider Program -> Get started.