Was it simple and elegant from the beginning, or did it click at some point? I started learning it from the O'Reily book yesterday, and so far it's easily the steepest learning curve for a language.
In my honest opinion, lifetimes should be hand waved until you've played with the rest of the language. By then it'll follow as naturally as your first lesson on OOP.
I wouldn't recommend the O'Reilly book for a beginner, use the official book in the docs, and do Rustlings alongside that. That's how I learned. Rustlings especially smooths you into the concepts while the O'Reilly book starts off writing a Mandelbrot generator as the first project, which put me off of that.
It's steeper than Haskell?
I can only compare to C, perl, ruby, python or bash.
sarcasm
In my opinion, books are the worst way to learn a programming language. Reading existing codebases and watching tutorials is usually far more effective, especially when you can mostly transfer knowledge of how to do things in one language to another.