Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I love the ability that Safari supports Airplay for it's video content:
22199581my.jpg


It is not necessary to mirror the full desktop, which makes youtubing a lot less laggy and more convenient (I don't like the native Apple TV app)
 
No UI lag with a smooth and improved Mission Control + Metal (for pro apps like Adobe CC), performance improvements across the board (love the faster PDF in Preview). This alone makes El Capitan worth it.
 
Anybody figured out what "Time to leave" and "File copy resume" does?

Time to leave: Sounds like something related to transit or directions; Calendar and/or Maps?
File copy resume: Surely this means we can now pause/resume while copying in Finder?
 
Tie between no more UI lag and split screen... I love Atom and Terminal side by side in full screen.
 
The cross of Mission Control and Leopard's Exposé. Much more usable IMO instead of having the overlapping windows. That drove me nuts.

The option to hide the menu bar is nice but pointless for me. If I didn't want to see it I'd enter full screen.
 
Sounds unintuitive. Is there actually any other kind of behaviour that is activated by a long button press? I can't think of one off the top of my head. Why not do it like all these third-party apps, Windows and some Linux desktop environments do by dragging the window into a corner or to the side? That's how lots of similar functions work in Finder.

Cue Force Touch!
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.