Comparison is the bread and butter of discussion. The problem is when people forget that an album should also be examined on it's own, in addition to comparing it to other albums.
Hear, hear.
I think
Virtual XI &
Brave New World often come to mind as a pair of Iron Maiden albums with particularly interesting comparatible elements;
musically even more so than often bundled up
The X-Factor &
Virtual XI, I think.
While the return of two major songwriters, Adrian and Bruce, definitely gives the material of Brave New World lots of edge to begin with, there is still lots of shared musical DNA with Virtual XI: Blood Brothers, The Nomad, The Mercenary, Dream of Mirrors and maybe even The Thin Line Between Love & Hate. It really underlines how the different approach to the recording and the whole production process, along with the new-found spark with the returning members makes such a big difference. Even with very much identical production values and/or stylistic choices Brave New World would obviously be a superior album, but looking at it without the "reunion celebration" factor, those two albums definitely share a lot more than some fans (not here of course!) are, sometimes, willing to admit.
All this makes those two albums particularly interesting pair in my book. Outside these, I'm not too big on these direct comparisons. Of course it's always interesting to look at the relation of any pair of albums that follow each other, but especially now, as the gaps between the releases have become rather long, I think they're slightly... less-reflective of each other, in a way. Then again,
The Book of Souls &
Senjutsu sit very comfortably together and have very distinctive and different vibe when compared to The Final Frontier and it's predecessors... so in that sense, they're a good match and I often compared these two a lot.
Okay, another interesting "transition" and therefore intriguing comparative is
Seventh Son of a Seventh Son &
No Prayer for the Dying. Of course the line-up
and the stylistic change is there, along with very different production approach, but I also think there are some things on these albums that link slightly more seamlessly than a lot of people often (at least out loud) acknowledge. There are certainly similarities at the use of keyboards, for example, although they're not quite as upfront on
No Prayer. A lot of people also consider
No Prayer as a dramatic turn in Bruce's approach to singing, but when looking at the stuff recorded at 1988, both studio and live, I think there's a very audible change into raspier-than-before Bruce well before 1990. E.g Charlotte & Prowler '88 and live recordings like Donington '88 have some relatively raspy performances as well; when it comes to live situation, part of it might have been that Bruce's vocal chords were quite shot at the time with the relentless touring and often catching a flu on the road, but anyway.