Just to chime in, I've been reading drafts of this steadily (I think I've seen one or more forms of nearly all of it by now), and it's outstanding. I think it should be especially good for intermediate Vim users, but even newer ones could get a lot out of it.
I'm the author. Practical Vim is currently available as a beta book - containing 17 out of 20 chapters. I'll publish a new chapter every two weeks until it's complete.