I have to agree with Cymbel here. Gravity is your enemy. I would give chain the nod on mobility in the short term, but only if the game has turn by turn rules for how tired you get and how that effects you.
Seriously, if you fight for more rounds (in a row) in chain than you have toughness, you should get Fatigued. It is not condusive to efficient maneuvering. That doesn't mean you'd get fatigue every turn after, but people couldn't fight for very long in armor. Moving from one fight to the next, okay, moving to engage a new opponent, sure, but in the constant press you get tired and then you die.
Articulated plate on the other hand was much better for fighting. technology. I know the M41 doesn't have a handle on it anymore, but it doesn't mean we have to forget.