You’re good to go: I read it on a Kindle Paperwhite in landscape orientation and I don’t recall any reading woes or having to jump back to code examples.
Yeah, it’s a biggie. 
I don’t quite remember how long it took, mainly because I got interrupted with another book I had to read for work.
But it didn’t feel too long because:
- I was getting so much foundation
- Joe’s writing style is great
And if it helps, you could consider it as four books in sequence, given the way the book is structured into four parts:
- Sequential Erlang
- Concurrent and Distributed Programs
- Programming Libraries and Frameworks
- Building Applications
