Oh man, I hear you on Dark Tower 7 and Pet Semetary. And I still love Firestarter to this day - I think it's definitely one of his strongest novels.

In answer to your question: Definitely Soul Eater, no contest. I am enjoying Not!, probably a lot more than a lot of the fandom does, but it still doesn't hold a candle to the main series.

Question! Since you mentioned satisfying endings... What is your most favorite, satisfying, perfect ending to anything ever?