Gun to head, I'm an old school Maiden fan (the first rock concert I ever saw was Maiden opening for Priest; what a standard, huh?) but I'm not sure there's a band around from the 80's that is as consistently making progressive music like Maiden. I get the knock, that Maiden isn't exactly reinventing themselves every album, but having said that, there's a far greater distance between, say, Book Of Souls or AMOLAD and, say, Seventh Son than Black Ice and Flick Of The Switch, or Hardwired and Master of Puppets.