For playing v/s strong defensive teams using 4-5-1v see my fact no#9.
Man on man marking means to follow every player within your pitch half.Since your defense will be flexibly positioned,if opponent had dribbler or playmaker special ability or opponent is strong in quality then man on man marking fails.

Zonal marking is best if opponent is strong by quality and you want to defensive counter attacks.
Anyways,I have written (marking style thoery) you can search in this forum or in google type marking style thoery top eleven.
Any other help?