For quite a while now, I’ve had Caps Lock mapped to Escape. At first it was just out of convenience — as a vim user, I use Escape much more than Caps Lock. With the new MacBook Pro keyboards it’s somewhat of a necessity.
I had a great, but complex, setup that I copied from Brett Terpstra where Caps Lock was Escape if you pressed it by itself, but Control + Option + Command + Shift if you held it down with another key. This worked great for global hotkeys, especially when combined with an app like Snap, because that complex combination of keys is uncommon anywhere else. When Sierra was introduced, the super glue and duct tape fell apart, and the global hotkeys stopped working.
It looks like this was recently fixed with Karabiner Elements though; and it’s much easier now. There are some pre-made rules on the author’s website. I copied the caps lock recipe to GitHub for posterity. After installing Karabiner Elements from Github, you can automatically install the caps lock rules with a specially crafted link: