Complexity is relative; some of this depends on you. But I think Grande Armée could be described as "intermediate" in complexity. The rules-portion of the rulebook is about 40 pages. All charts and tables fit on one double-sided sheet.

I have taught the game to complete novices at many conventions. The tutorial usually takes half an hour, and most people have mastered the game by Turn 2.

Playing time depends again on the players; everybody plays at a different pace. The average game seems to run about four hours. I don't know about you, but that's usually all I'm good for these days!