Sven bender is more suited to a defensive role eg. BWM, DM, or Anchor man where as Matic can easily play as a Deep-lying playmaker as hes better going forward than sven bender.
In real life I would go for Matic... absolute machine. As has been said he probably is more of a player thats going to make things happen going forward compared S.Bender who is a better as an out an out defensive player. So it is really what you are looking for in your role.