I honestly can't make up my mind either, right now I got ACIV and I'm debating if I want return it for NFS Rivals or Lego Marvel Super heroes.Both game series I'm not really a fan of, Assassins Creed I tried 1 & 2 and just could not get into them.
Need For Speed the last one I remember playing was NFS Paradise. I'm big fan of Gran Turismo and will be getting GT 6 next month for PS3.
I might consider just returning the game at Walmart for store credit since they will allow returns on un opened games with no recite, and use it later when more games release next year.