El Cap has been good to me except for two issues:
1. SuperDuper clones wouldn't boot.
2. USB keyboard and mouse lost power upon waking the computer. I had to do a hard shutdown and restart to get everything working. This is very erratic; doesn't happen often but happens haphazardly.
The first issue was solved by cloning with Carbon Copy Cloner. The 10.11.2 update may fix the second issue but it's too early to tell.
Otherwise, El Cap is fine for me.
Jon
macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365
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