I wish I could say that I found this a great ending to a series and a splendid book in itself, but I really can't.
Where I sort of liked the previous novel, which had a good cliffhanger and some interesting twists, this part is just a simple clash between good and evil. All of the good ones are honourable (even ready to die for a cause), whilst those who are bad are overconfident and scurry away like rats when they are no longer winning.
Granted, I did not see the final reveal coming and I was pleasantly surprised by that. But then again, how can you see anything coming when you are constantly switching between storylines, timelines, shadowrealms, prophecy-forks and what not. And this is one of this books major flaws: It is overly complex, whilst trying to stay simple, making everything feel cramped in or heaped up in a hurry and most of all wrong (I'm not going to discuss the everlasting problems with time-travel, but let's just say this is also far from perfect/believable).
I have the feeling that in stead of maturing the books along with the audience, Michael Scott 'immatured' into b-type fiction, giving me that empty 3-star feeling.