LYAH is a bit dated, but since it focuses a lot more on conceptual stuff, instead of being directly pragmatic, it has aged a lot better than books like "Real World Haskell".

The main concepts are presented well, but people have complained about it being dated. What in particular do you find outdated?

I saw someone confused on haskell-cafe yesterday because it doesn't cover Applicative so their Monad instance was invalid.

Oof that is bad. I admit that I only used it to learn the basic concepts that just did exercises and read the prelude documentation ( which is fantastic ). Thanks for letting me know.