I've been hoping to pick it up on weekends & time off but startup hours don't leave much free time. I worked on a few simple heroku / json phoenix apps last year. Hoping I can put together a useful but small web app next.
I started phoenix before fully understanding Elixir and had a hard time. Then I got that book and when I was halfway through I loved Elixir already.
Now I use phoenix for almost everything web related.