Looking across the updates in El Capitan, the story is clear: Apple is making life way better for people who live in its ecosystem. But if you don’t live in Apple’s garden, the benefits are less clear. Yes, it’s faster and there are bugfixes all around, but to take advantage of Apple’s updates you really need to use Apple’s apps.
I just want El Capitan’s Metal and Aero Snap. That name is horrible, though.