grandis ka na kung 4x2 fortuner lang din yung comparison. that means, you'll be using the fortuner like a minivan, and the grandis is a better minivan than the fortuner. performance-wise and features-wise, grandis wins.
but of course, if you want the style of a macho SUV, then go for the Fortuner. there's a reason why the fortuner sells so well and the grandis doesn't, and i'm sure that a large part of it is styling and image.