This is an interesting question.
It seems that most of the sexfights/titfights that appear on the net are between younger women. But personally I would love to see two women in their 40's or 50's engage in such a contest. I can't exactly explain why, but the idea of two mature women in a sexfight is a real turn-on to me.
As for a real, nasty catfight, again, most of the vids on the net feature younger women fighting. But I would love to see two mature women in a full on fight.