One is a defensive-midfielder, one is a center-midfielder.
Jedinak is superior in; Defensive Position, Intercepting, Heading, Holding the ball up and tackling.
Bjarny is superior in; carrying the ball through midfield, forward passing, and shooting.
My point being, you cannot compare them to one another...it completely depends on the opposition's game-plan as to which is more effective. Tonight for example, QPR will be playing a lot of balls in the air, so having Jedinak heading the ball right back into their half will be more effective. (in my opinion)