My main problem with RWH (and I'm not alone in saying this) is that the first 4 chapters are insufficient to prepare you for the material in the rest of the book.
Read "Programming in Haskell" by Graham Hutton first. It's a small book... I literally did the whole thing (including implementing all the exercises) in a week. To call it excellent would be the understatement of the century.
From there, pick up RWH. You can skim the first few chapters, and you'll be much better equipped to read the rest of them.
From there, pick up RWH. You can skim the first few chapters, and you'll be much better equipped to read the rest of them.