I love Stephen King, I really do. Thus far anything I've read of his has been engaging and filled with wonderful, vibrant characters. So I picked up The Dark Tower expecting the same. 
 I can describe TDT in one word: vague. The characters are vague, the backstory is vague, the motivation is vague, even the setting/time is rather vague. I honestly could not tell you what on earth was going on for the better part of the story. Even so, I always enjoy King's prose--simple yet complex.