Interestingly, it's rare to see anyone pick anything other than the Castle, Fortress, Watchtower, Mausoleum, or Wizard's Tower, with the castle by far the overwhelming favorite. Very rarely somebody will take a fortified city (and lose), and some newbie's first game may invoke a Dark Citadel, but nobody ever takes the Mountain Citadel: To understand what the strengths of the mountain citadel over the dark citadel are, you'd have to not be a newbie, as the stats on paper look better for the Dark Citadel....but if you're not a newbie, you're probably not taking EITHER of these hideously expensive yet poor admin forts.
