At the Apple event today, we finally learned that Mac OS X 10.9 Mavericks is available today. I already went over the new Finder tabs, iBooks for Macs, Finder tags, and improved full-screen apps in my hands-on for Mavericks in June, but Apple gave us a recap to talk about what the OS does beyond the new features.
Along with new features, Apple says part of the idea behind Mavericks is to get the most out of your hardware, and Apple says improvements to energy management get you as much as an hour more for Web browsing, simply by installing the new OS. It also has improved graphics, and better processing power to make the whole OS more efficient.
The big news today is that Apple has changed its OS pricing. Mavericks is free even if you're using older versions of the OS as far back as Snow Leopard, which was released in 2007.
Editors' note: I'll be updating this story throughout the day as I get more information about Mavericks.