I have had Evernote working on El Capitan for a while now, but suddenly this weekend the spinner appeared a couple of seconds after launch and did not recover, Force Quit required. I tried installing the free versions of the Caecilia font I could find, but that did not work. I just downloaded the 6.3 Beta and that seems to be working, but its not ideal. I was doing some web clipping over the weekend before this happened in case there is a link there. The web app and my iOS apps seem to be working fine, so I know these bugs are tricky to find. Hope that helps.