No, I'm generally happy with it. This is what I said in another thread:
I love El Capitan. It's not perfect; I can definitely tell it's a .0 release:
- Finder crashed and had to be force quit when moving files from my VM
- When you try to close a background iTunes window, it jumps to the front of the screen and changes the active app as if it was on Windows (iTunes only)
- iTunes froze 3 times when trying to play a movie while it was downloading.
- Some slight but unusual stutter from time to time.
- Hasn't fixed the bug where some PDFs open fuzzy until you resize them
- Some Safari scrolling bugs.
HOWEVER, the overall improvement with system performance is nice, the new system font is much more pleasant than Helvetica Neuve
and it fixes the worst bug that made me want to punch my screen:
I have a Dell ultrasharp 2415H that I use when in clamshell mode. Under Yosemite, my monitor would randomly blank out and come back on for unknown reasons. I would have to unplug it, switch display ports, etc to make it work and when I turned the monitor off, the system recognized it as a disconnect and moved all of my windows over to another monitor. I thought it was the display so I almost threw it out because it was so bad. Ever since updating to EC on Wednesday, I have had one blink or flash. No disconnection, nothing. I'm using the same setup, the same cables, and the same ports. Maybe it's dumb luck, or maybe EC fixed some kind of graphic driver? I wasn't expecting a monitor fix, but this has been a great surprise. This bug fix alone is enough to make me endure any little bugs present in the .0 release.
EDIT: the UI tweaks are welcome as well! I'm partially color-blind, and Yosemite's harsh all flat with white buttons on light gray gradients didn't work well for me. Maybe it's just me, but grays seem slightly darker, buttons now have a slight bulge to them, and there appears to be a greater use of drop shadows.