For the most part, I immensely enjoyed Song of Susannah. It's a fast-paced novel with plenty of surprises, revelations, and much more. 
 The 2nd Stanza, in particular, really stands out for me, as it sets up the rest of the book quite nicely. And King does it so seamlessly. 
 I think the entire Tet are developed well, but that of Eddie Dean is truly exceptional. I love how irate he became over Calvin Tower's obsession with his precious books. In this scene, the reader realizes just how far Eddie has come from his former lifestyle, which is exactly why he was so very angry. Even Roland takes note by his rather candid question: "You want to kill him, don't you?" 
 Along with this comes the development of their dinh, Jake, Father Callahan.. even Oy, to some degree. 
 But in light of the novel's apt title, I would have liked to see more emphasis on Susannah's character development, as opposed to Mia and their chap. 
 Speaking of which, I think that said sub-plot tends to drag on slightly. At the same time, I realize that in the long run, it all takes place in a relatively short amount of time... it probably just seems a lot longer because it's interspersed throughout the entire novel. 
 I also loved the notion of Susannah's Dogan being her subconscious, and the various personalities combating one another and also working together in unique ways. 
 The insertion of "the writer" is very interesting, too. I loved it the 1st time I read it, and this was no exception. It's brilliant, yet quite ballsy. I clearly understand why so many readers would be turned off by what could easily be perceived as arrogance on King's part, or a God complex, if you will. 
 And the opening scene of the chapter where Eddie and Roland not only sense the enormous power of the forest, but actually see the omnipresent faces is truly awe inspiring. I love, love, LOVE that scene! 
 Last but certainly not least, the reader is left with quite a cliffhanger at the end. You just NEED to know what happens next!