So I may have acquired a pre-release CD of this prior to Friday and am giving it my first listen now. The first song sounds like something right off of Chemical Wedding, it's unreal how similar the vibe is, there's even a spoken word acoustic outro with that weird voice modulation he used on Accident of Birth.
So, first listen done. Standout tracks for me are Eternity Should Fail, When the River Runs Deep, Book of Souls, Tears of a Clown and Empire of the Clouds. Empire is so majestic, the first 5 minutes or so don't really sound like Maiden at all.
Can't say for sure after only one listen but it's definitely one of their strongest albums. There's definitely some filler in there but none of it really sounds as sterile as a lot of Final Frontier did. There's so much variety on this album, some of it a lot heavier than anything Maiden have done before, some of it not really sounding like conventional Maiden at all.