Larry Smith wrote on Thu, Oct 16, 2008 07:47 PM UTC:
In the Mad Queen variant, the player is able to gain or recover pieces through promotion of the Pawn.
In Shogi, not only do many of the pieces promote but the player also gains an opponent's material through capture.
In XiangQi, except for the increase in power of the Soldier there are no promotions. What you see is what you get.
Like most Westerns I was first introduced to the Mad Queen variant. During military service, I came into contact with and played Shogi and XiangQi. There was always other players of the Mad Queen but those of Shogi and XiangQi were rare. That was until common access to the internet(I actually played a text-based game of Mad Queen across the fledgling internet at a technology exposition in Houston when I was a Boy Scout).
I enjoy all three games very much, and have real-world sets of each.