My opinion:
The Astonishing is a great record, I admire DT for trying something so different, so late in their career, kinda like Rush did with Clockwork Angels (which worked in a similar enviorment, story-wise.)
I think this album will grow more on me, but so far I quite like it. It has some flaws, of course (some of the melodies are not that original in my opinion, and I could've done well with less songs dealing with the same topic - ex.: Begin Again/Act Of Faythe, The X Aspect/Moment Of Betrayal. I would've liked a song about Nafaryus' childhood, or a song from Daryus' POV, after he goes deaf.)
But, really, this album works spectacularly for its purpose: telling a story. It's one of the most creative DT albums too, and one that is so varied in the emotional spectrum. I laugh listening to Three Days, same as I cry during Astonishing or Losing Faythe.
Overall, it's really capable of putting you into The Great Northen Empire and follow the story that's unfolding.
As far as songs IMO:
FAVORITES:
A Better Life
Ravenskill (probably my favorite overall)
Three Days
Act Of Faythe
Chosen
A Savior In The Square/When Your Time Has Come
The Walking Shadow
The Path That Divides
Astonishing
I still have to get into some tracks, but damn.
Also, James really shines in this record. It's his redemption for all the instrumental wankery of the past