The Number of the Beast was a messy transition album that was not as raw and energetic as Killers, not as refined as Piece of Mind, and not half as good as either. "Hallowed Be Thy Name" is the classic of classics, but "Invaders" is goofy, "22 Acacia Avenue" is dull, "Run to the Hills" is pushing accessibility a bit too far, and "Gangland" sucks in every aspect.
Also, people who complain that progressive metal doesn't progress towards anything don't understand that "progressive" in progressive rock came from the Progressive radio format, not some fundamental progression in the music. Progressive metal is simply the distinguishing characteristics of progressive rock (either in part or in full) transferred to metal. What people want "progressive metal" to mean is actually avant-garde metal.
never before or since has a band created a sound that's so bludgeoningly huge in every respect, let alone integrated that sound with an otherworldly mysticism that adds completely new dimensions. the whole thing just has this vast, epic, mythical quality that shouldn't work but is forced into fruition by the band's ability to flaunt subtlety and class without sacrificing the no-bullshit core. it actually sounds like real demigods at work. you've got to at least admit the title track is amazing.
