Driving in Chicago a couple days ago I heard a radio review of the new Mastodon album (I think it was on WLUP) and they commented about it having more complex musicianship and composition. Then one reviewer said it "has an almost, dare I say it, prog-rock style in parts" and then followed that with " it reminds me of early Rush, and I mean that in a good way." Then the other reviewer said "Absolutely! I can still recall when I first heard A Farewell To Kings and it just blew me away".
I only heard part of the review and didn't have time to make note of who was talking. It might have been Jim Derogatis or Greg Kot. It certainly made me want to consider checking out the album to see if any of it rings true to my ears. It's always nice to hear rock critics willing to share those kinds of opinions on the air.