A stable and refined OS X release
From Rene Richie’s OS X El Capitan first look piece on iMore:
As Snow Leopard refined and advanced Leopard, as Mountain Lion refined and advanced Lion, so too is OS X El Capitan intended to refine and advance last year's OS X Yosemite. That means the focus isn't on major redesigns or profound system-level changes, though there is a little of both to be found. Instead, Apple is making OS X smarter, and giving it considerably more polish.
For El Cap, that means new window management options, including an improved Mission Control and new Split View. The company has made Spotlight smarter and improved stock OS X apps like Notes, Safari, Mail, Maps, and Photos. They've enhanced performance, stability, and security—including bringing iOS graphics framework Metal to the Mac. They've even added new system fonts: San Francisco for alphabetic languages; Ping Fang for Chinese; tweaks to the Japanese system font, Hiragino Sans; and improved input methods for both Chinese and Japanese.
“Stability” and “polish” are the two words that sum up every “My first week with El Cap” review I’ve read so far, which means that this release is shaping up to be everything I wanted. The Yosemite release was a shambles in many regards but it appears that Apple has gone most, if not all the way, towards fixing it this year.
As usual, I’m tempted to jump onboard with the first developer beta but will try and hold off, at least until the public beta release.